64Mb: x4, x8, x16

SDRAM

SYNCHRONOUS MT48LC16M4A2 - 4 Meg x 4 x 4 banks

MT48LC8M8A2 - 2 Meg x 8 x 4 banks

DRAM MT48LC4M16A2 - 1 Meg x 16 x 4 banks

For the latest data sheet, please refer to the Micron Web
site: www.micron.com/mti/msp/html/datasheet.html

FEATURES
• PC66-, PC100- and PC133-compliant
PIN ASSIGNMENT (Top View)
• 143 MHz, graphical 4 Meg x 16 option
• Fully synchronous; all signals registered on positive
54-Pin TSOP
edge of system clock x4 x8 x16 x16 x8 x4
- - VDD 1 54 Vss - -
• Internal pipelined operation; column address can NC DQ0 DQ0 2 53 DQ15 DQ7 NC
be changed every clock cycle - - VDDQ 3 52 VssQ - -
NC NC DQ1 4 51 DQ14 NC NC
• Internal banks for hiding row access/precharge DQ0 DQ1 DQ2 5 50 DQ13 DQ6 DQ3
• Programmable burst lengths: 1, 2, 4, 8 or full page - - VssQ 6 49 VDDQ - -
NC NC DQ3 7 48 DQ12 NC NC
• Auto Precharge, includes CONCURRENT AUTO NC DQ2 DQ4 8 47 DQ11 DQ5 NC
PRECHARGE, and Auto Refresh Modes - - VDDQ 9 46 VssQ - -
NC NC DQ5 10 45 DQ10 NC NC
• Self Refresh Modes: standard and low power DQ1 DQ3 DQ6 11 44 DQ9 DQ4 DQ2
• 64ms, 4,096-cycle refresh - - VssQ 12 43 VDDQ - -
NC NC DQ7 13 42 DQ8 NC NC
• LVTTL-compatible inputs and outputs - - VDD 14 41 Vss - -
• Single +3.3V ±0.3V power supply NC NC DQML 15 40 NC - -
- - WE# 16 39 DQMH DQM DQM
- - CAS# 17 38 CLK - -
OPTIONS MARKING -
-
- RAS#
- CS#
18
19
37
36
CKE
NC
-
-
-
-
• Configurations - - BA0 20 35 A11 - -
- - BA1 21 34 A9 - -
16 Meg x 4 (4 Meg x 4 x 4 banks) 16M4 - - A10 22 33 A8 - -
8 Meg x 8 (2 Meg x 8 x 4 banks) 8M8 - - A0 23 32 A7 - -
- - A1 24 31 A6 - -
4 Meg x 16 (1 Meg x 16 x 4 banks) 4M16 - - A2 25 30 A5 - -
- - A3 26 29 A4 - -
• WRITE Recovery (tWR) - - VDD 27 28 Vss - -
t
WR = “2 CLK”1 A2
Note: The # symbol indicates signal is active LOW. A dash (–)
• Plastic Package - OCPL2 indicates x8 and x4 pin function is same as x16 pin function.
54-pin TSOP II (400 mil) TG 16 Meg x 4 8 Meg x 8 4 Meg x 16
Configuration 4 Meg x 4 x 4 banks 2 Meg x 8 x 4 banks 1 Meg x 16 x 4 banks
• Timing (Cycle Time)
Refresh Count 4K 4K 4K
10ns @ CL2 (PC100) -8E Row Addressing 4K (A0-A11) 4K (A0-A11) 4K (A0-A11)
7.5ns @ CL3 (PC133) -75 Bank Addressing 4 (BA0, BA1) 4 (BA0, BA1) 4 (BA0, BA1)
7.5ns @ CL2 (PC133) -7E Column Addressing 1K (A0-A9) 512 (A0-A8) 256 (A0-A7)
7ns @ CL3 (143 MHz) -7G3
• Self Refresh
Standard None KEY TIMING PARAMETERS
Low Power L
SPEED CLOCK ACCESS TIME SETUP HOLD
• Operating Temperature Range GRADE FREQUENCY CL = 2* CL = 3* TIME TIME
Commercial (0°C to +70°C) None -7G 143 MHz – 6ns 2ns 1ns
Extended (-40°C to +85°C) IT4 -7E 143 MHz – 5.4ns 1.5ns 0.8ns
-75 133 MHz – 5.4ns 1.5ns 0.8ns
Part Number Example:
-8E 125 MHz – 6ns 2ns 1ns
MT48LC8M8A2TG-8E -7E 133 MHz 5.4ns – 1.5ns 0.8ns
NOTE: 1. Refer to Micron Technical Note TN-48-05. -75 100 MHz 6ns – 1.5ns 0.8ns
2. Off-center parting line. -8E 100 MHz 6ns – 2ns 1ns
3. Available on 4 Meg x 16.
4. Available on x8, x16, -8E.
* CL = CAS (READ) latency

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 1 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

64Mb SDRAM PART NUMBERS

command are used to select the starting column loca-
PART NUMBER ARCHITECTURE tion for the burst access.
MT48LC16M4A2TG 16 Meg x 4 The SDRAM provides for programmable READ or
MT48LC8M8A2TG 8 Meg x 8 WRITE burst lengths of 1, 2, 4 or 8 locations, or the
MT48LC4M16A2TG 4 Meg x 16 full page, with a burst terminate option. An auto
precharge function may be enabled to provide a self-
timed row precharge that is initiated at the end of the
GENERAL DESCRIPTION burst sequence.
The 64Mb SDRAM is a high-speed CMOS, dynamic The 64Mb SDRAM uses an internal pipelined
random-access memory containing 67,108,864 bits. It architecture to achieve high-speed operation. This
is internally configured as a quad-bank DRAM with a architecture is compatible with the 2n rule of prefetch
synchronous interface (all signals are registered on the architectures, but it also allows the column address to
positive edge of the clock signal, CLK). Each of the x4’s be changed on every clock cycle to achieve a high-
16,777,216-bit banks is organized as 4,096 rows by speed, fully random access. Precharging one bank while
1,024 columns by 4 bits. Each of the x8’s 16,777,216-bit accessing one of the other three banks will hide the
banks is organized as 4,096 rows by 512 columns by 8 precharge cycles and provide seamless, high-speed,
bits. Each of the x16’s 16,777,216-bit banks is organized random-access operation.
as 4,096 rows by 256 columns by 16 bits. The 64Mb SDRAM is designed to operate in 3.3V
Read and write accesses to the SDRAM are burst memory systems. An auto refresh mode is provided,
oriented; accesses start at a selected location and con- along with a power-saving, power-down mode.
tinue for a programmed number of locations in a All inputs and outputs are LVTTL-compatible.
programmed sequence. Accesses begin with the SDRAMs offer substantial advances in DRAM oper-
registration of an ACTIVE command, which is then ating performance, including the ability to synchro-
followed by a READ or WRITE command. The address nously burst data at a high data rate with automatic
bits registered coincident with the ACTIVE command column-address generation, the ability to interleave
are used to select the bank and row to be accessed (BA0, between internal banks in order to hide precharge time
BA1 select the bank; A0-A11 select the row). The address and the capability to randomly change column
bits registered coincident with the READ or WRITE addresses on each clock cycle during a burst access.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 2 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

TABLE OF CONTENTS
Functional Block Diagram - 16 Meg x 4 ................. 4 Concurrent Auto Precharge ......................... 25
Functional Block Diagram - 8 Meg x 8 ................. 5 Truth Table 2 (CKE) ................................................. 27
Functional Block Diagram - 4 Meg x 16 ............... 6 Truth Table 3 (Current State, Same Bank) .................. 28
Pin Descriptions ..................................................... 7 Truth Table 4 (Current State, Different Bank) ............. 30
Functional Description ......................................... 8 Absolute Maximum Ratings ................................... 32
Initialization ...................................................... 8 DC Electrical Characteristics
Register Definition ............................................ 8 and Operating Conditions ................................... 32
Mode Register ............................................... 8 IDD Specifications and Conditions ......................... 32
Burst Length ............................................ 8 Capacitance ............................................................ 33
Burst Type ............................................... 9 Electrical Characteristics and Recommended
CAS Latency ............................................ 10 Operating Conditions (Timing Table) ............. 33
Operating Mode ...................................... 10
Timing Waveforms
Write Burst Mode .................................... 10
Initialize and Load Mode Register ..................... 36
Commands ........................................................ 11
Power-Down Mode ............................................ 37
Truth Table 1 (Commands and DQM Operation) ....... 11
Clock Suspend Mode ......................................... 38
Command Inhibit ........................................ 12
Auto Refresh Mode ............................................ 39
No Operation (NOP) .................................... 12
Self Refresh Mode .............................................. 40
Load Mode Register ...................................... 12
Reads
Active ............................................................ 12
Read - Without Auto Precharge ................... 41
Read .............................................................. 12
Read - With Auto Precharge ......................... 42
Write ............................................................. 12
Single Read - Without Auto Precharge ........ 43
Precharge ...................................................... 12
Single Read - With Auto Precharge .............. 44
Auto Precharge ............................................. 12
Alternating Bank Read Accesses ................... 45
Burst Terminate ............................................ 12
Read - Full-Page Burst ................................... 46
Auto Refresh ................................................. 13
Read - DQM Operation ................................ 47
Self Refresh ................................................... 13
Writes
Operation .......................................................... 14
Write - Without Auto Precharge .................. 48
Bank/Row Activation ................................... 14
Write - With Auto Precharge ....................... 49
Reads ............................................................ 15
Single Write - Without Auto Precharge ....... 50
Writes ........................................................... 21
Single Write - With Auto Precharge ............. 51
Precharge ...................................................... 23
Alternating Bank Write Accesses ................. 52
Power-Down ................................................. 23
Write - Full-Page Burst ................................. 53
Clock Suspend .............................................. 24
Write - DQM Operation ............................... 54
Burst Read/Single Write ............................... 24

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 3 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

FUNCTIONAL BLOCK DIAGRAM

16 Meg x 4 SDRAM

CKE
CLK

CS# CONTROL
COMMAND

LOGIC
DECODE

WE#
BANK3
CAS# BANK2
RAS# BANK1

REFRESH 12
MODE REGISTER COUNTER
ROW- 12 BANK0
ADDRESS ROW- BANK0
MUX ADDRESS MEMORY 1 1
12 4096
LATCH ARRAY DQM
12 & (4,096 x 1,024 x 4)
DECODER

SENSE AMPLIFIERS DATA

4 OUTPUT
4096 REGISTER

2 I/O GATING 4 DQ0-DQ3

DQM MASK LOGIC
BANK READ DATA LATCH
A0-A11, ADDRESS CONTROL WRITE DRIVERS
BA0, BA1 14
REGISTER LOGIC DATA
2 4 INPUT
1024 REGISTER
(x4)

COLUMN
DECODER
COLUMN-
ADDRESS 10
10 COUNTER/
LATCH

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 4 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

FUNCTIONAL BLOCK DIAGRAM

8 Meg x 8 SDRAM

CKE
CLK

CS# CONTROL
COMMAND

LOGIC
DECODE

WE#
BANK3
CAS# BANK2
RAS# BANK1

REFRESH 12
MODE REGISTER COUNTER
ROW- 12 BANK0
ADDRESS ROW- BANK0
MUX ADDRESS MEMORY 1 1
12 4096
LATCH ARRAY DQM
12 & (4,096 x 512 x 8)
DECODER

SENSE AMPLIFIERS DATA

8 OUTPUT
4096 REGISTER

2 I/O GATING 8 DQ0-DQ7

DQM MASK LOGIC
BANK READ DATA LATCH
A0-A11, ADDRESS CONTROL WRITE DRIVERS
BA0, BA1 14
REGISTER LOGIC DATA
2 8 INPUT
512 REGISTER
(x8)

COLUMN
DECODER
COLUMN-
ADDRESS 9
9 COUNTER/
LATCH

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 5 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

FUNCTIONAL BLOCK DIAGRAM

4 Meg x 16 SDRAM

CKE
CLK

CS# CONTROL
COMMAND

LOGIC
DECODE

WE#
BANK3
CAS# BANK2
RAS# BANK1

REFRESH 12
MODE REGISTER COUNTER
ROW- 12 BANK0
ADDRESS ROW- BANK0
MUX ADDRESS MEMORY 2 2
12 4096
LATCH ARRAY DQML,
12 & (4,096 x 256 x 16) DQMH
DECODER

SENSE AMPLIFIERS DATA

16 OUTPUT
4096 REGISTER

2 I/O GATING 16 DQ0-DQ15

DQM MASK LOGIC
BANK READ DATA LATCH
A0-A11, ADDRESS CONTROL WRITE DRIVERS
BA0, BA1 14
REGISTER LOGIC DATA
2 16 INPUT
256 REGISTER
(x16)

COLUMN
DECODER
COLUMN-
ADDRESS 8
8 COUNTER/
LATCH

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 6 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

PIN DESCRIPTIONS
PIN NUMBERS SYMBOL TYPE DESCRIPTION
38 CLK Input Clock: CLK is driven by the system clock. All SDRAM input signals are
sampled on the positive edge of CLK. CLK also increments the internal
burst counter and controls the output registers.
37 CKE Input Clock Enable: CKE activates (HIGH) and deactivates (LOW) the CLK
signal. Deactivating the clock provides PRECHARGE POWER-DOWN and
SELF REFRESH operation (all banks idle), ACTIVE POWER-DOWN (row
active in any bank) or CLOCK SUSPEND operation (burst/access in
progress). CKE is synchronous except after the device enters power-
down and self refresh modes, where CKE becomes asynchronous until
after exiting the same mode. The input buffers, including CLK, are
disabled during power-down and self refresh modes, providing low
standby power. CKE may be tied HIGH.
19 CS# Input Chip Select: CS# enables (registered LOW) and disables (registered
HIGH) the command decoder. All commands are masked when CS# is
registered HIGH. CS# provides for external bank selection on systems
with multiple banks. CS# is considered part of the command code.
16, 17, 18 WE#, CAS#, Input Command Inputs: WE#, CAS# and RAS# (along with CS#) define the
RAS# command being entered.
39 x4, x8: DQM Input Input/Output Mask: DQM is an input mask signal for write accesses and
an output enable signal for read accesses. Input data is masked when
15, 39 x16: DQML, DQM is sampled HIGH during a WRITE cycle. The output buffers are
DQMH placed in a High-Z state (two-clock latency) when DQM is sampled
HIGH during a READ cycle. On the x4 and x8, DQML (Pin 15) is a NC and
DQMH is DQM. On the x16, DQML corresponds to DQ0-DQ7 and
DQMH corresponds to DQ8-DQ15. DQML and DQMH are considered
same state when referenced as DQM.
20, 21 BA0, BA1 Input Bank Address Inputs: BA0 and BA1 define to which bank the ACTIVE,
READ, WRITE or PRECHARGE command is being applied.
23-26, 29-34, 22, 35 A0-A11 Input Address Inputs: A0-A11 are sampled during the ACTIVE command (row-
address A0-A11) and READ/WRITE command (column-address A0-A9
[x4]; A0-A8 [x8]; A0-A7 [x16]; with A10 defining auto precharge) to
select one location out of the memory array in the respective bank. A10
is sampled during a PRECHARGE command to determine if all banks are
to be precharged (A10 HIGH) or bank selected by BA0, BA1 (LOW). The
address inputs also provide the op-code during a LOAD MODE
REGISTER command.
2, 4, 5, 7, 8, 10, 11, 13, 42, DQ0-DQ15 x16: I/O Data Input/Output: Data bus for x16 (4, 7, 10, 13, 42, 45, 48, 51 are
44, 45, 47, 48, 50, 51, 53 NCs for x8; and 2, 4, 7, 8, 10, 13, 42, 45, 47, 48, 51, 53 are NCs for x4).
2, 5, 8, 11, 44, 47, 50, 53 DQ0-DQ7 x8: I/O Data Input/Output: Data bus for x8 (2, 8, 47, 53 are NCs for x4).
5, 11, 44, 50 DQ0-DQ3 x4: I/O Data Input/Output: Data bus for x4.
36, 40 NC – No Connect: These pins should be left unconnected.
3, 9, 43, 49 VDDQ Supply DQ Power: Isolated DQ power on the die for improved noise immunity.
6, 12, 46, 52 VSSQ Supply DQ Ground: Isolated DQ ground on the die for improved noise
immunity.
1, 14, 27 VDD Supply Power Supply: +3.3V ±0.3V.
28, 41, 54 VSS Supply Ground.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 7 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

FUNCTIONAL DESCRIPTION Register Definition

In general, the 64Mb SDRAMs (4 Meg x 4 x 4 banks, MODE REGISTER
2 Meg x 8 x 4 banks and 1 Meg x 16 x 4 banks) are quad- The mode register is used to define the specific mode
bank DRAMs which operate at 3.3V and include a of operation of the SDRAM. This definition includes
synchronous interface (all signals are registered on the the selection of a burst length, a burst type, a CAS
positive edge of the clock signal, CLK). Each of the x4’s latency, an operating mode and a write burst mode, as
16,777,216-bit banks is organized as 4,096 rows by shown in Figure 1. The mode register is programmed
1,024 columns by 4 bits. Each of the x8’s 16,777,216-bit via the LOAD MODE REGISTER command and will
banks is organized as 4,096 rows by 512 columns by 8 retain the stored information until it is programmed
bits. Each of the x16’s 16,777,216-bit banks is organized again or the device loses power.
as 4,096 rows by 256 columns by 16 bits. Mode register bits M0-M2 specify the burst length,
Read and write accesses to the SDRAM are burst M3 specifies the type of burst (sequential or inter-
oriented; accesses start at a selected location and con- leaved), M4-M6 specify the CAS latency, M7 and M8
tinue for a programmed number of locations in a specify the operating mode, M9 specifies the WRITE
programmed sequence. Accesses begin with the regis- burst mode, and M10 and M11 are reserved for future
tration of an ACTIVE command which is then followed use.
by a READ or WRITE command. The address bits regis- The mode register must be loaded when all banks are
tered coincident with the ACTIVE command are used idle, and the controller must wait the specified time
to select the bank and row to be accessed (BA0 and BA1 before initiating the subsequent operation. Violating
select the bank, A0-A11 select the row). The address bits either of these requirements will result in unspecified
(x4: A0-A9; x8: A0-A8; x16: A0-A7) registered coinci- operation.
dent with the READ or WRITE command are used to
select the starting column location for the burst access. Burst Length
Prior to normal operation, the SDRAM must be Read and write accesses to the SDRAM are burst
initialized. The following sections provide detailed oriented, with the burst length being programmable, as
information covering device initialization, register defi- shown in Figure 1. The burst length determines the
nition, command descriptions and device operation. maximum number of column locations that can be
accessed for a given READ or WRITE command. Burst
Initialization lengths of 1, 2, 4 or 8 locations are available for both the
SDRAMs must be powered up and initialized in a sequential and the interleaved burst types, and a full-
predefined manner. Operational procedures other than page burst is available for the sequential type. The full-
those specified may result in undefined operation. page burst is used in conjunction with the BURST
Once power is applied to VDD and VDDQ (simulta- TERMINATE command to generate arbitrary burst
neously) and the clock is stable (stable clock is defined lengths.
as a signal cycling within timing constraints specified Reserved states should not be used, as unknown
for the clock pin), the SDRAM requires a 100µs delay operation or incompatibility with future versions may
prior to issuing any command other than a COM- result.
MAND INHIBIT or a NOP. Starting at some point during When a READ or WRITE command is issued, a block
this 100µs period and continuing at least through the of columns equal to the burst length is effectively
end of this period, COMMAND INHIBIT or NOP com- selected. All accesses for that burst take place within
mands should be applied. this block, meaning that the burst will wrap within the
Once the 100µs delay has been satisfied with at least block if a boundary is reached. The block is uniquely
one COMMAND INHIBIT or NOP command having selected by A1-A9 (x4), A1-A8 (x8) or A1-A7 (x16) when
been applied, a PRECHARGE command should be ap- the burst length is set to two; by A2-A9 (x4), A2-A8 (x8)
plied. All banks must be precharged, thereby placing or A2-A7 (x16) when the burst length is set to four; and
the device in the all banks idle state. by A3-A9 (x4), A3-A8 (x8) or A3-A7 (x16) when the burst
Once in the idle state, two AUTO REFRESH cycles length is set to eight. The remaining (least significant)
must be performed. After the AUTO REFRESH cycles are address bit(s) is (are) used to select the starting location
complete, the SDRAM is ready for mode register pro- within the block. Full-page bursts wrap within the page
gramming. Because the mode register will power up in if the boundary is reached.
an unknown state, it should be loaded prior to applying
any operational command.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 8 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM
Burst Type Table 1
Accesses within a given burst may be programmed Burst Definition
to be either sequential or interleaved; this is referred to
as the burst type and is selected via bit M3.
Burst Starting Column Order of Accesses Within a Burst
The ordering of accesses within a burst is deter-
Length Address Type = Sequential Type = Interleaved
mined by the burst length, the burst type and the
starting column address, as shown in Table 1. A0
0 0-1 0-1
2
1 1-0 1-0
A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 Address Bus A1 A0
0 0 0-1-2-3 0-1-2-3
0 1 1-2-3-0 1-0-3-2
4
11 10 9 8 7 6 5 4 3 2 1 0
Mode Register (Mx)
1 0 2-3-0-1 2-3-0-1
Reserved* WB Op Mode CAS Latency BT Burst Length 1 1 3-0-1-2 3-2-1-0
A2 A1 A0
*Should program 0 0 0 0-1-2-3-4-5-6-7 0-1-2-3-4-5-6-7
M11, M10 = “0, 0”
to ensure compatibility Burst Length 0 0 1 1-2-3-4-5-6-7-0 1-0-3-2-5-4-7-6
with future devices.
M2 M1 M0 M3 = 0 M3 = 1 0 1 0 2-3-4-5-6-7-0-1 2-3-0-1-6-7-4-5
0 0 0 1 1
0 1 1 3-4-5-6-7-0-1-2 3-2-1-0-7-6-5-4
0 0 1 2 2 8
1 0 0 4-5-6-7-0-1-2-3 4-5-6-7-0-1-2-3
0 1 0 4 4

0 1 1 8 8
1 0 1 5-6-7-0-1-2-3-4 5-4-7-6-1-0-3-2
1 0 0 Reserved Reserved 1 1 0 6-7-0-1-2-3-4-5 6-7-4-5-2-3-0-1
1 0 1 Reserved Reserved 1 1 1 7-0-1-2-3-4-5-6 7-6-5-4-3-2-1-0
1 1 0 Reserved Reserved Cn, Cn + 1, Cn + 2
1 1 1 Full Page Reserved
Full n = A0-A9/8/7
Cn + 3, Cn + 4...
Page Not Supported
…Cn - 1,
(y) (location 0-y)
Cn…
M3 Burst Type

0 Sequential

1 Interleaved NOTE: 1. For full-page accesses: y = 1,024 (x4); y = 512 (x8);

y = 256 (x16).
M6 M5 M4 CAS Latency 2. For a burst length of two, A1-A9 (x4), A1-A8 (x8),
0 0 0 Reserved or A1-A7 (x16) select the block-of-two burst; A0
0 0 1 Reserved selects the starting column within the block.
0 1 0 2 3. For a burst length of four, A2-A9 (x4), A2-A8 (x8),
0 1 1 3 or A2-A7 (x16) select the block-of-four burst; A0-
1 0 0 Reserved A1 select the starting column within the block.
1 0 1 Reserved 4. For a burst length of eight, A3-A9 (x4), A3-A8
1 1 0 Reserved (x8), or A3-A7 (x16) select the block-of-eight
1 1 1 Reserved burst; A0-A2 select the starting column within the
block.
5. For a full-page burst, the full row is selected and
M8 M7 M6-M0 Operating Mode A0-A9 (x4), A0-A8 (x8), or A0-A7 (x16) select the
0 0 Defined Standard Operation starting column.
- - - All other states reserved 6. Whenever a boundary of the block is reached
within a given sequence above, the following
access wraps within the block.
M9 Write Burst Mode
7. For a burst length of one, A0-A9 (x4), A0-A8 (x8),
0 Programmed Burst Length
or A0-A7 (x16) select the unique column to be
1 Single Location Access
accessed, and mode register bit M3 is ignored.

Figure 1
Mode Register Definition

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 9 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM
CAS Latency Operating Mode
The CAS latency is the delay, in clock cycles, be- The normal operating mode is selected by setting
tween the registration of a READ command and the M7 and M8 to zero; the other combinations of values
availability of the first piece of output data. The latency for M7 and M8 are reserved for future use and/or test
can be set to two or three clocks. modes. The programmed burst length applies to both
If a READ command is registered at clock edge n, and READ and WRITE bursts.
the latency is m clocks, the data will be available by Test modes and reserved states should not be used
clock edge n + m. The DQs will start driving as a result because unknown operation or incompatibility with
of the clock edge one cycle earlier (n + m - 1), and future versions may result.
provided that the relevant access times are met, the
data will be valid by clock edge n + m. For example, Write Burst Mode
assuming that the clock cycle time is such that all When M9 = 0, the burst length programmed via
relevant access times are met, if a READ command is M0-M2 applies to both READ and WRITE bursts; when
registered at T0 and the latency is programmed to two M9 = 1, the programmed burst length applies to
clocks, the DQs will start driving after T1 and the data READ bursts, but write accesses are single-location
will be valid by T2, as shown in Figure 2. Table 2 (nonburst) accesses.
indicates the operating frequencies at which each CAS
latency setting can be used.
Reserved states should not be used as unknown Table 2
operation or incompatibility with future versions CAS Latency
may result.
ALLOWABLE OPERATING
T0 T1 T2 T3
FREQUENCY (MHz)
CLK CAS CAS
SPEED LATENCY = 2 LATENCY = 3
COMMAND READ NOP NOP
-7G – ≤ 143
tLZ tOH
-7E ≤ 133 ≤ 143
DQ DOUT
tAC -75 ≤ 100 ≤ 133
-8E ≤ 100 ≤ 125
CAS Latency = 2

T0 T1 T2 T3 T4
CLK

COMMAND READ NOP NOP NOP

tLZ tOH

DQ DOUT
tAC

CAS Latency = 3

DON’T CARE

UNDEFINED

Figure 2
CAS Latency

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SDRAM

Commands
Truth Table 1 provides a quick reference of Tables appear following the Operation section; these
available commands. This is followed by a written tables provide current state/next state information.
description of each command. Three additional Truth

TRUTH TABLE 1 – COMMANDS AND DQM OPERATION

(Notes: 1)

NAME (FUNCTION) CS# RAS# CAS# WE# DQM ADDR DQs NOTES
COMMAND INHIBIT (NOP) H X X X X X X
NO OPERATION (NOP) L H H H X X X
ACTIVE (Select bank and activate row) L L H H X Bank/Row X 3
READ (Select bank and column, and start READ burst) L H L H L/H8 Bank/Col X 4
WRITE (Select bank and column, and start WRITE burst) L H L L L/H8 Bank/Col Valid 4
BURST TERMINATE L H H L X X Active
PRECHARGE (Deactivate row in bank or banks) L L H L X Code X 5
AUTO REFRESH or SELF REFRESH L L L H X X X 6, 7
(Enter self refresh mode)
LOAD MODE REGISTER L L L L X Op-Code X 2
Write Enable/Output Enable – – – – L – Active 8
Write Inhibit/Output High-Z – – – – H – High-Z 8

NOTE: 1. CKE is HIGH for all commands shown except SELF REFRESH.
2. A0-A11 define the op-code written to the mode register.
3. A0-A11 provide row address, and BA0, BA1 determine which bank is made active.
4. A0-A9 (x4), A0-A8 (x8), or A0-A7 (x16) provide column address; A10 HIGH enables the auto precharge feature
(nonpersistent), while A10 LOW disables the auto precharge feature; BA0, BA1 determine which bank is being read
from or written to.
5. A10 LOW: BA0, BA1 determine the bank being precharged. A10 HIGH: All banks precharged and BA0, BA1 are “Don’t
Care.”
6. This command is AUTO REFRESH if CKE is HIGH, SELF REFRESH if CKE is LOW.
7. Internal refresh counter controls row addressing; all inputs and I/Os are “Don’t Care” except for CKE.
8. Activates or deactivates the DQs during WRITEs (zero-clock delay) and READs (two-clock delay).

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SDRAM
COMMAND INHIBIT
The COMMAND INHIBIT function prevents new determines whether or not auto precharge is used. If
commands from being executed by the SDRAM, regard- auto precharge is selected, the row being accessed will
less of whether the CLK signal is enabled. The SDRAM be precharged at the end of the WRITE burst; if auto
is effectively deselected. Operations already in progress precharge is not selected, the row will remain open for
are not affected. subsequent accesses. Input data appearing on the DQs
is written to the memory array subject to the DQM
NO OPERATION (NOP) input logic level appearing coincident with the data. If
The NO OPERATION (NOP) command is used to a given DQM signal is registered LOW, the correspond-
perform a NOP to an SDRAM which is selected (CS# is ing data will be written to memory; if the DQM signal
LOW). This prevents unwanted commands from being is registered HIGH, the corresponding data inputs will
registered during idle or wait states. Operations already be ignored, and a WRITE will not be executed to that
in progress are not affected. byte/column location.

LOAD MODE REGISTER PRECHARGE

The mode register is loaded via inputs A0-A11. See The PRECHARGE command is used to deactivate the
mode register heading in the Register Definition section. open row in a particular bank or the open row in all
The LOAD MODE REGISTER command can only be issued banks. The bank(s) will be available for a subsequent
when all banks are idle, and a subsequent executable row access a specified time (tRP) after the PRECHARGE
command cannot be issued until tMRD is met. command is issued. Input A10 determines whether one
or all banks are to be precharged, and in the case where
ACTIVE only one bank is to be precharged, inputs BA0, BA1
The ACTIVE command is used to open (or activate) select the bank. Otherwise BA0, BA1 are treated as
a row in a particular bank for a subsequent access. The “Don’t Care.” Once a bank has been precharged, it is in
value on the BA0, BA1 inputs selects the bank, and the the idle state and must be activated prior to any READ
address provided on inputs A0-A11 selects the row. This or WRITE commands being issued to that bank.
row remains active (or open) for accesses until a
PRECHARGE command is issued to that bank. AUTO PRECHARGE
A PRECHARGE command must be issued before open- Auto precharge is a feature which performs the same
ing a different row in the same bank. individual-bank PRECHARGE function described above,
without requiring an explicit command. This is accom-
READ plished by using A10 to enable auto precharge in
The READ command is used to initiate a burst read conjunction with a specific READ or WRITE command.
access to an active row. The value on the BA0, BA1 A precharge of the bank/row that is addressed with the
inputs selects the bank, and the address provided on READ or WRITE command is automatically performed
inputs A0-A9 (x4), A0-A8 (x8), or A0-A7 (x16) selects the upon completion of the READ or WRITE burst, except
starting column location. The value on input A10 in the full-page burst mode, where auto precharge does
determines whether or not auto precharge is used. If not apply. Auto precharge is nonpersistent in that it is
auto precharge is selected, the row being accessed will either enabled or disabled for each individual READ or
be precharged at the end of the READ burst; if auto WRITE command.
precharge is not selected, the row will remain open for Auto precharge ensures that the precharge is initi-
subsequent accesses. Read data appears on the DQs ated at the earliest valid stage within a burst. The user
subject to the logic level on the DQM inputs two clocks must not issue another command to the same bank
earlier. If a given DQM signal was registered HIGH, the until the precharge time (tRP) is completed. This is
corresponding DQs will be High-Z two clocks later; if determined as if an explicit PRECHARGE command was
the DQM signal was registered LOW, the DQs will issued at the earliest possible time, as described for each
provide valid data. burst type in the Operation section of this data sheet.

WRITE BURST TERMINATE

The WRITE command is used to initiate a burst write The BURST TERMINATE command is used to trun-
access to an active row. The value on the BA0, BA1 cate either fixed-length or full-page bursts. The most
inputs selects the bank, and the address provided on recently registered READ or WRITE command prior to
inputs A0-A9 (x4), A0-A8 (x8), or A0-A7 (x16) selects the the BURST TERMINATE command will be truncated, as
starting column location. The value on input A10 shown in the Operation section of this data sheet.

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SDRAM
AUTO REFRESH
AUTO REFRESH is used during normal operation of Once the SELF REFRESH command is registered, all the
the SDRAM and is analagous to CAS#-BEFORE-RAS# inputs to the SDRAM become “Don’t Care,” with the
(CBR) REFRESH in conventional DRAMs. This com- exception of CKE, which must remain LOW.
mand is nonpersistent, so it must be issued each time a Once self refresh mode is engaged, the SDRAM
refresh is required. provides its own internal clocking, causing it to per-
The addressing is generated by the internal refresh form its own AUTO REFRESH cycles. The SDRAM must
controller. This makes the address bits “Don’t Care” remain in self refresh mode for a minimum period
during an AUTO REFRESH command. The 64Mb SDRAM equal to tRAS and may remain in self refresh mode for
requires 4,096 AUTO REFRESH cycles every 64ms (tREF), an indefinite period beyond that.
regardless of width option. Providing a distributed The procedure for exiting self refresh requires a
AUTO REFRESH command every 15.625µs will meet sequence of commands. First, CLK must be stable (stable
the refresh requirement and ensure that each row is clock is defined as a signal cycling within timing
refreshed. Alternatively, 4,096 AUTO REFRESH com- constraints specified for the clock pin) prior to CKE
mands can be issued in a burst at the minimum cycle going back HIGH. Once CKE is HIGH, the SDRAM must
rate (tRC), once every 64ms. have NOP commands issued (a minimum of two clocks)
for tXSR, because time is required for the completion of
SELF REFRESH any internal refresh in progress.
The SELF REFRESH command can be used to retain Upon exiting the self refresh mode, AUTO REFRESH
data in the SDRAM, even if the rest of the system is commands must be issued every 15.625µs or less as
powered down. When in the self refresh mode, the both SELF REFRESH and AUTO REFRESH utilize the row
SDRAM retains data without external clocking. refresh counter.
The SELF REFRESH command is initiated like an AUTO
REFRESH command except CKE is disabled (LOW).

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Operation CLK
BANK/ROW ACTIVATION
Before any READ or WRITE commands can be issued CKE HIGH
to a bank within the SDRAM, a row in that bank must
be “opened.” This is accomplished via the ACTIVE
command, which selects both the bank and the row to CS#
be activated (see Figure 3).
After opening a row (issuing an ACTIVE command),
a READ or WRITE command may be issued to that row, RAS#
subject to the tRCD specification. tRCD (MIN) should
be divided by the clock period and rounded up to the
next whole number to determine the earliest clock edge CAS#
after the ACTIVE command on which a READ or WRITE
command can be entered. For example, a tRCD specifi- WE#
cation of 20ns with a 125 MHz clock (8ns period) results
in 2.5 clocks, rounded to 3. This is reflected in Figure 4,
which covers any case where 2 < tRCD (MIN)/tCK ≤ 3. ROW
A0-A11
(The same procedure is used to convert other specifica- ADDRESS
tion limits from time units to clock cycles).
A subsequent ACTIVE command to a different row
in the same bank can only be issued after the previous BA0, BA1 BANK
ADDRESS
active row has been “closed” (precharged). The mini-
mum time interval between successive ACTIVE com-
mands to the same bank is defined by tRC.
A subsequent ACTIVE command to another bank
can be issued while the first bank is being accessed, Figure 3
which results in a reduction of total row-access over- Activating a Specific Row in a
head. The minimum time interval between successive
ACTIVE commands to different banks is defined by
Specific Bank
tRRD.

T0 T1 T2 T3 T4

CLK

COMMAND READ or
ACTIVE NOP NOP
WRITE

tRCD

DON’T CARE

Figure 4
Example: Meeting tRCD (MIN) When 2 < tRCD (MIN)/tCK < 3

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READs
READ bursts are initiated with a READ command, as Upon completion of a burst, assuming no other
shown in Figure 5. commands have been initiated, the DQs will go High-
The starting column and bank addresses are pro- Z. A full-page burst will continue until terminated. (At
vided with the READ command, and auto precharge is the end of the page, it will wrap to column 0 and
either enabled or disabled for that burst access. If auto continue.)
precharge is enabled, the row being accessed is Data from any READ burst may be truncated with a
precharged at the completion of the burst. For the subsequent READ command, and data from a fixed-
generic READ commands used in the following illustra- length READ burst may be immediately followed by
tions, auto precharge is disabled. data from a READ command. In either case, a continu-
During READ bursts, the valid data-out element ous flow of data can be maintained. The first data
from the starting column address will be available element from the new burst follows either the last
following the CAS latency after the READ command. element of a completed burst or the last desired data
Each subsequent data-out element will be valid by the element of a longer burst which is being truncated.
next positive clock edge. Figure 6 shows general timing
for each possible CAS latency setting.

T0 T1 T2 T3
CLK
CLK

CKE HIGH COMMAND READ NOP NOP

tLZ tOH

CS# DQ DOUT
tAC

CAS Latency = 2
RAS#

CAS# T0 T1 T2 T3 T4
CLK

WE#
COMMAND READ NOP NOP NOP
tLZ tOH
A0-A9: x4 COLUMN
A0-A8: x8 ADDRESS DQ DOUT
A0-A7: x16 tAC

A11: x4
A9, A11: x8 CAS Latency = 3
A8, A9, A11: x16 DON’T CARE

ENABLE AUTO PRECHARGE UNDEFINED

A10
DISABLE AUTO PRECHARGE
Figure 6
BA0,1 BANK CAS Latency
ADDRESS

Figure 5
READ Command

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The new READ command should be issued x cycles does not require the 2n rule associated with a prefetch
before the clock edge at which the last desired data architecture. A READ command can be initiated on any
element is valid, where x equals the CAS latency minus clock cycle following a previous READ command. Full-
one. This is shown in Figure 7 for CAS latencies of two speed random read accesses can be performed to the
and three; data element n + 3 is either the last of a burst same bank, as shown in Figure 8, or each subsequent
of four or the last desired of a longer burst. The 64Mb READ may be performed to a different bank.
SDRAM uses a pipelined architecture and therefore

T0 T1 T2 T3 T4 T5 T6

CLK

COMMAND READ NOP NOP NOP READ NOP NOP

X = 1 cycle

BANK, BANK,
ADDRESS COL n COL b

DOUT DOUT DOUT DOUT DOUT

DQ n n+1 n+2 n+3 b

CAS Latency = 2

T0 T1 T2 T3 T4 T5 T6 T7

CLK

COMMAND READ NOP NOP NOP READ NOP NOP NOP

X = 2 cycles

BANK, BANK,
ADDRESS COL n COL b

DOUT DOUT DOUT DOUT DOUT

DQ n n+1 n+2 n+3 b

CAS Latency = 3

NOTE: Each READ command may be to any bank. DQM is LOW. DON’T CARE

Figure 7
Consecutive READ Bursts

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T0 T1 T2 T3 T4 T5

CLK

COMMAND READ READ READ READ NOP NOP

BANK, BANK, BANK, BANK,

ADDRESS COL n COL a COL x COL m

DOUT DOUT DOUT DOUT

DQ n a x m

CAS Latency = 2

T0 T1 T2 T3 T4 T5 T6

CLK

COMMAND READ READ READ READ NOP NOP NOP

BANK, BANK, BANK, BANK,

ADDRESS COL n COL a COL x COL m

DOUT DOUT DOUT DOUT

DQ n a x m

CAS Latency = 3

NOTE: Each READ command may be to any bank. DQM is LOW.

DON’T CARE
Figure 8
Random READ Accesses

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Data from any READ burst may be truncated with a buffers) to suppress data-out from the READ. Once the
subsequent WRITE command, and data from a fixed- WRITE command is registered, the DQs will go High-Z
length READ burst may be immediately followed by (or remain High-Z), regardless of the state of the DQM
data from a WRITE command (subject to bus turn- signal, provided the DQM was active on the clock just
around limitations). The WRITE burst may be initiated prior to the WRITE command that truncated the READ
on the clock edge immediately following the last (or command. If not, the second WRITE will be an invalid
last desired) data element from the READ burst, pro- WRITE. For example, if DQM was LOW during T4 in
vided that I/O contention can be avoided. In a given Figure 10, then the WRITEs at T5 and T7 would be valid,
system design, there may be a possibility that the while the WRITE at T6 would be invalid.
device driving the input data will go Low-Z before the The DQM signal must be de-asserted prior to the
SDRAM DQs go High-Z. In this case, at least a single- WRITE command (DQM latency is zero clocks for input
cycle delay should occur between the last read data and buffers) to ensure that the written data is not masked.
the WRITE command. Figure 9 shows the case where the clock frequency
The DQM input is used to avoid I/O contention, as allows for bus contention to be avoided without adding
shown in Figures 9 and 10. The DQM signal must be a NOP cycle, and Figure 10 shows the case where the
asserted (HIGH) at least two clocks prior to the WRITE additional NOP is needed.
command (DQM latency is two clocks for output

T0 T1 T2 T3 T4 T5

T0 T1 T2 T3 T4 CLK

CLK
DQM

DQM
COMMAND READ NOP NOP NOP NOP WRITE

COMMAND READ NOP NOP NOP WRITE BANK, BANK,

ADDRESS COL n COL b
tHZ
BANK, BANK,
ADDRESS COL n COL b
DQ DOUT n DIN b
tCK tDS
tHZ

DOUT n DIN b NOTE: A CAS latency of three is used for illustration. The READ command
DQ
may be to any bank, and the WRITE command may be to any bank.
tDS
DON’T CARE
NOTE: A CAS latency of three is used for illustration.
The READ command may be to any bank, and the WRITE
command may be to any bank. If a burst of one is used, Figure 10
then DQM is not required.
DON’T CARE
READ to WRITE With
Extra Clock Cycle
Figure 9
READ to WRITE

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SDRAM
A fixed-length READ burst may be followed by, or the last desired of a longer burst. Following the
truncated with, a PRECHARGE command to the same PRECHARGE command, a subsequent command to the
bank (provided that auto precharge was not activated), same bank cannot be issued until tRP is met. Note that
and a full-page burst may be truncated with a part of the row precharge time is hidden during the
PRECHARGE command to the same bank. The access of the last data element(s).
PRECHARGE command should be issued x cycles before In the case of a fixed-length burst being executed to
the clock edge at which the last desired data element is completion, a PRECHARGE command issued at the
valid, where x equals the CAS latency minus one. This optimum time (as described above) provides the same
is shown in Figure 11 for each possible CAS latency; operation that would result from the same fixed-length
data element n + 3 is either the last of a burst of four or burst with auto precharge. The disadvantage of the

T0 T1 T2 T3 T4 T5 T6 T7

CLK

t RP

COMMAND READ NOP NOP NOP PRECHARGE NOP NOP ACTIVE

X = 1 cycle
BANK a, BANK BANK a,
ADDRESS COL n (a or all) ROW

DOUT DOUT DOUT DOUT

DQ n n+1 n+2 n+3

CAS Latency = 2

T0 T1 T2 T3 T4 T5 T6 T7

CLK

t RP

COMMAND READ NOP NOP NOP PRECHARGE NOP NOP ACTIVE

X = 2 cycles
BANK a, BANK BANK a,
ADDRESS COL n (a or all) ROW

DOUT DOUT DOUT DOUT

DQ n n+1 n+2 n+3

CAS Latency = 3

NOTE: DQM is LOW. DON’T CARE

Figure 11
READ to PRECHARGE

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PRECHARGE command is that it requires that the command, provided that auto precharge was not acti-
command and address buses be available at the appro- vated. The BURST TERMINATE command should be
priate time to issue the command; the advantage of the issued x cycles before the clock edge at which the last
PRECHARGE command is that it can be used to trun- desired data element is valid, where x equals the CAS
cate fixed-length or full-page bursts. latency minus one. This is shown in Figure 12 for each
Full-page READ bursts can be truncated with the possible CAS latency; data element n + 3 is the last
BURST TERMINATE command, and fixed-length READ desired data element of a longer burst.
bursts may be truncated with a BURST TERMINATE

T0 T1 T2 T3 T4 T5 T6

CLK

BURST
COMMAND READ NOP NOP NOP
TERMINATE
NOP NOP

X = 1 cycle
BANK,
ADDRESS COL n

DOUT DOUT DOUT DOUT

DQ n n+1 n+2 n+3

CAS Latency = 2

T0 T1 T2 T3 T4 T5 T6 T7

CLK

BURST
COMMAND READ NOP NOP NOP
TERMINATE
NOP NOP NOP

X = 2 cycles
BANK,
ADDRESS COL n

DOUT DOUT DOUT DOUT

DQ n n+1 n+2 n+3

CAS Latency = 3

NOTE: DQM is LOW. DON’T CARE

Figure 12
Terminating a READ Burst

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WRITEs
WRITE bursts are initiated with a WRITE command, An example is shown in Figure 15. Data n + 1 is either
as shown in Figure 13. the last of a burst of two or the last desired of a longer
The starting column and bank addresses are burst. The 64Mb SDRAM uses a pipelined architecture
provided with the WRITE command, and auto precharge and therefore does not require the 2n rule associated
is either enabled or disabled for that access. If auto with a prefetch architecture. A WRITE command can be
precharge is enabled, the row being accessed is initiated on any clock cycle following a previous WRITE
precharged at the completion of the burst. For the command. Full-speed random write accesses within a
generic WRITE commands used in the following illus- page can be performed to the same bank, as shown in
trations, auto precharge is disabled. Figure 16, or each subsequent WRITE may be performed
During WRITE bursts, the first valid data-in element to a different bank.
will be registered coincident with the WRITE com-
mand. Subsequent data elements will be registered on T0 T1 T2 T3
each successive positive clock edge. Upon completion
CLK
of a fixed-length burst, assuming no other commands
have been initiated, the DQs will remain High-Z and
any additional input data will be ignored (see Figure
COMMAND WRITE NOP NOP NOP
14). A full-page burst will continue until terminated.
(At the end of the page, it will wrap to column 0 and
continue.) ADDRESS
BANK,
COL n
Data for any WRITE burst may be truncated with a
subsequent WRITE command, and data for a fixed-
length WRITE burst may be immediately followed by DQ
DIN DIN
n n+1
data for a WRITE command. The new WRITE command
can be issued on any clock following the previous
WRITE command, and the data provided coincident
NOTE: Burst length = 2. DQM is LOW.
with the new command applies to the new command.
Figure 14
CLK WRITE Burst
CKE HIGH

CS# T0 T1 T2

CLK
RAS#

CAS# COMMAND WRITE NOP WRITE

WE#
BANK, BANK,
ADDRESS COL n COL b
A0-A9: x4 COLUMN
A0-A8: x8 ADDRESS
A0-A7: x16
A11: x4 DIN DIN DIN
A9, A11: x8
DQ n n+1 b
A8, A9, A11: x16
ENABLE AUTO PRECHARGE
A10
DISABLE AUTO PRECHARGE
NOTE: DQM is LOW. Each WRITE
command may be to any bank.

BANK
BA0,1 ADDRESS DON’T CARE

Figure 13 Figure 15
WRITE Command WRITE to WRITE

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Data for any WRITE burst may be truncated with a the clock edge at which the last desired input data
subsequent READ command, and data for a fixed- element is registered. The auto precharge mode re-
length WRITE burst may be immediately followed by a quires a tWR of at least one clock plus time, regardless
subsequent READ command. Once the READ com- of frequency. In addition, when truncating a WRITE
mand is registered, the data inputs will be ignored, and burst, the DQM signal must be used to mask input data
WRITEs will not be executed. An example is shown in for the clock edge prior to, and the clock edge coinci-
Figure 17. Data n + 1 is either the last of a burst of two dent with, the PRECHARGE command. An example is
or the last desired of a longer burst. shown in Figure 18. Data n + 1 is either the last of a burst
Data for a fixed-length WRITE burst may be fol- of two or the last desired of a longer burst. Following the
lowed by, or truncated with, a PRECHARGE command PRECHARGE command, a subsequent command to the
to the same bank (provided that auto precharge was not same bank cannot be issued until tRP is met.
activated), and a full-page WRITE burst may be trun- In the case of a fixed-length burst being executed to
cated with a PRECHARGE command to the same bank. completion, a PRECHARGE command issued at the
The PRECHARGE command should be issued tWR after optimum time (as described above) provides the same
operation that would result from the same fixed-length
burst with auto precharge. The disadvantage of the
T0 T1 T2 T3 PRECHARGE command is that it requires that the
command and address buses be available at the appro-
CLK priate time to issue the command; the advantage of the
PRECHARGE command is that it can be used to trun-
cate fixed-length or full-page bursts.
COMMAND WRITE WRITE WRITE WRITE

T0 T1 T2 T3 T4 T5 T6
BANK, BANK, BANK, BANK,
ADDRESS COL n COL a COL x COL m
CLK

tWR@ tCK 15ns

DIN DIN DIN DIN DQM

DQ n a x m
t RP

COMMAND WRITE NOP PRECHARGE NOP NOP ACTIVE NOP

NOTE: Each WRITE command may be to any bank.
DQM is LOW. BANK a, BANK BANK a,
ADDRESS COL n (a or all) ROW

Figure 16 DIN DIN

t WR

DQ
Random WRITE Cycles n n+1

tWR@ tCK < 15ns

T0 T1 T2 T3 T4 T5 DQM

CLK t RP

COMMAND WRITE NOP NOP PRECHARGE NOP NOP ACTIVE

COMMAND WRITE NOP READ NOP NOP NOP BANK a, BANK BANK a,
ADDRESS COL n (a or all) ROW

t WR

BANK, BANK, DIN DIN

ADDRESS DQ n n+1
COL n COL b

DIN DIN DOUT DOUT NOTE: DQM could remain LOW in this example if the WRITE burst is a fixed
DQ n n+1 b b+1 length of two.

DON’T CARE
NOTE: The WRITE command may be to any bank, and the READ command may
be to any bank. DQM is LOW. CAS latency = 2 for illustration.
Figure 18
Figure 17 WRITE to PRECHARGE
WRITE to READ

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SDRAM
Fixed-length or full-page WRITE bursts can be trun- PRECHARGE
cated with the BURST TERMINATE command. When The PRECHARGE command (Figure 20) is used to
truncating a WRITE burst, the input data applied coin- deactivate the open row in a particular bank or the open
cident with the BURST TERMINATE command will be row in all banks. The bank(s) will be available for a
ignored. The last data written (provided that DQM is subsequent row access some specified time (tRP) after
LOW at that time) will be the input data applied one the PRECHARGE command is issued. Input A10 deter-
clock previous to the BURST TERMINATE command. mines whether one or all banks are to be precharged,
This is shown in Figure 19, where data n is the last and in the case where only one bank is to be precharged,
desired data element of a longer burst. inputs BA0, BA1 select the bank. When all banks are to
be precharged, inputs BA0, BA1 are treated as “Don’t
Care.” Once a bank has been precharged, it is in the idle
T0 T1 T2
state and must be activated prior to any READ or WRITE
CLK commands being issued to that bank.

BURST NEXT
POWER-DOWN
COMMAND WRITE
TERMINATE COMMAND Power-down occurs if CKE is registered LOW coinci-
dent with a NOP or COMMAND INHIBIT when no
BANK, (ADDRESS)
accesses are in progress. If power-down occurs when all
ADDRESS COL n banks are idle, this mode is referred to as precharge
power-down; if power-down occurs when there is a row
DIN active in either bank, this mode is referred to as active
DQ (DATA)
n
power-down. Entering power-down deactivates the in-
put and output buffers, excluding CKE, for maximum
NOTE: DQMs are LOW. power savings while in standby. The device may not
remain in the power-down state longer than the refresh
Figure 19 period (64ms) since no refresh operations are per-
Terminating a WRITE Burst formed in this mode.
The power-down state is exited by registering a NOP
or COMMAND INHIBIT and CKE HIGH at the desired
CLK clock edge (meeting tCKS). See Figure 21.

CKE HIGH ((
))
CLK ((
))
CS# tCKS > tCKS

CKE ((
))

RAS# ((
))
COMMAND NOP NOP ACTIVE
((
))
All banks idle tRCD
CAS# Input buffers gated off tRAS
tRC
Enter power-down mode. Exit power-down mode.
WE#
DON’T CARE

A0-A9, A11
Figure 21
A10
All Banks
Power-Down
Bank Selected

BA0,1 BANK
ADDRESS

Figure 20
PRECHARGE Command

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SDRAM
CLOCK SUSPEND
The clock suspend mode occurs when a column Clock suspend mode is exited by registering CKE
access/burst is in progress and CKE is registered LOW. HIGH; the internal clock and related operation will
In the clock suspend mode, the internal clock is deac- resume on the subsequent positive clock edge.
tivated, “freezing” the synchronous logic.
For each positive clock edge on which CKE is sampled BURST READ/SINGLE WRITE
LOW, the next internal positive clock edge is sus- The burst read/single write mode is entered by
pended. Any command or data present on the input programming the write burst mode bit (M9) in the
pins at the time of a suspended internal clock edge is mode register to a logic 1. In this mode, all WRITE
ignored; any data present on the DQ pins remains commands result in the access of a single column
driven; and burst counters are not incremented, as long location (burst of one), regardless of the programmed
as the clock is suspended. (See examples in Figures 22 burst length. READ commands access columns accord-
and 23.) ing to the programmed burst length and sequence, just
as in the normal mode of operation (M9 = 0).

T0 T1 T2 T3 T4 T5 T0 T1 T2 T3 T4 T5 T6

CLK CLK

CKE
CKE

INTERNAL
INTERNAL CLOCK
CLOCK

COMMAND READ NOP NOP NOP NOP NOP

COMMAND NOP WRITE NOP NOP

BANK,
ADDRESS COL n
BANK,
ADDRESS COL n
DOUT DOUT DOUT DOUT
DQ n n+1 n+2 n+3

DIN DIN DIN

DQ n n+1 n+2
NOTE: For this example, CAS latency = 2, burst length = 4 or greater, and
DQM is LOW.
NOTE: For this example, burst length = 4 or greater, and DQM
is LOW. DON’T CARE

Figure 22 Figure 23
Clock Suspend During WRITE Burst Clock Suspend During READ Burst

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SDRAM
CONCURRENT AUTO PRECHARGE
An access command (READ or WRITE) to another on bank n, CAS latency later. The PRECHARGE to
bank while an access command with auto precharge bank n will begin when the READ to bank m is
enabled is executing is not allowed by SDRAMs, unless registered (Figure 24).
the SDRAM supports CONCURRENT AUTO 2. Interrupted by a WRITE (with or without auto
PRECHARGE. Micron SDRAMs support CONCURRENT precharge): A WRITE to bank m will interrupt a
AUTO PRECHARGE. Four cases where CONCURRENT READ on bank n when registered. DQM should be
AUTO PRECHARGE occurs are defined below. used two clocks prior to the WRITE command to
prevent bus contention. The PRECHARGE to bank n
READ with Auto Precharge will begin when the WRITE to bank m is registered
1. Interrupted by a READ (with or without auto (Figure 25).
precharge): A READ to bank m will interrupt a READ

T0 T1 T2 T3 T4 T5 T6 T7

CLK

READ - AP READ - AP
COMMAND NOP
BANK n
NOP
BANK m
NOP NOP NOP NOP

BANK n Page Active READ with Burst of 4 Interrupt Burst, Precharge Idle

Internal t RP - BANK n tRP - BANK m

States Page Active READ with Burst of 4 Precharge

BANK m

BANK n, BANK m,
ADDRESS COL a COL d

DOUT DOUT DOUT DOUT

DQ a a+1 d d+1

CAS Latency = 3 (BANK n)

NOTE: DQM is LOW. CAS Latency = 3 (BANK m)

Figure 24
READ With Auto Precharge Interrupted by a READ
T0 T1 T2 T3 T4 T5 T6 T7

CLK

READ - AP WRITE - AP
COMMAND BANK n
NOP NOP NOP
BANK m
NOP NOP NOP

Page
BANK n Active
READ with Burst of 4 Interrupt Burst, Precharge Idle

Internal tRP - BANK n t WR - BANK m

States Page Active WRITE with Burst of 4 Write-Back

BANK m

BANK n, BANK m,
ADDRESS COL a COL d

1
DQM

DOUT DIN DIN DIN DIN

DQ a d d+1 d+2 d+3

CAS Latency = 3 (BANK n)

NOTE: 1. DQM is HIGH at T2 to prevent DOUT-a+1 from contending with DIN-d at T4.

DON’T CARE

Figure 25
READ With Auto Precharge Interrupted by a WRITE

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SDRAM
WRITE with Auto Precharge
3. Interrupted by a READ (with or without auto 4. Interrupted by a WRITE (with or without auto
precharge): A READ to bank m will interrupt a WRITE precharge): A WRITE to bank m will interrupt a WRITE
on bank n when registered, with the data-out appear- on bank n when registered. The PRECHARGE to bank
ing CAS latency later. The PRECHARGE to bank n will n will begin after tWR is met, where tWR begins when
begin after tWR is met, where tWR begins when the the WRITE to bank m is registered. The last valid data
READ to bank m is registered. The last valid WRITE to WRITE to bank n will be data registered one clock prior
bank n will be data-in registered one clock prior to the to a WRITE to bank m (Figure 27).
READ to bank m (Figure 26).

T0 T1 T2 T3 T4 T5 T6 T7

CLK

WRITE - AP READ - AP
COMMAND NOP
BANK n
NOP
BANK m
NOP NOP NOP NOP

BANK n Page Active WRITE with Burst of 4 Interrupt Burst, Write-Back Precharge
tRP - BANK n
Internal tWR - BANK n
tRP - BANK m
States Page Active READ with Burst of 4
BANK m

BANK n, BANK m,
ADDRESS COL a COL d

DIN DIN DOUT DOUT

DQ a a+1 d d+1

CAS Latency = 3 (BANK m)

NOTE: 1. DQM is LOW.

Figure 26
WRITE With Auto Precharge Interrupted by a READ

T0 T1 T2 T3 T4 T5 T6 T7

CLK

WRITE - AP WRITE - AP
COMMAND NOP
BANK n
NOP NOP
BANK m
NOP NOP NOP

BANK n Page Active WRITE with Burst of 4 Interrupt Burst, Write-Back Precharge
tRP - BANK n
Internal tWR - BANK n
t WR - BANK m
States Page Active WRITE with Burst of 4 Write-Back
BANK m

BANK n, BANK m,
ADDRESS COL a COL d

DIN DIN DIN DIN DIN DIN DIN

DQ a a+1 a+2 d d+1 d+2 d+3

NOTE: 1. DQM is LOW.

DON’T CARE

Figure 27
WRITE With Auto Precharge Interrupted by a WRITE

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SDRAM

TRUTH TABLE 2 – CKE

(Notes: 1-4)
CKEn-1 CKEn CURRENT STATE COMMANDn ACTIONn NOTES
L L Power-Down X Maintain Power-Down
Self Refresh X Maintain Self Refresh
Clock Suspend X Maintain Clock Suspend
L H Power-Down COMMAND INHIBIT or NOP Exit Power-Down 5
Self Refresh COMMAND INHIBIT or NOP Exit Self Refresh 6
Clock Suspend X Exit Clock Suspend 7
H L All Banks Idle COMMAND INHIBIT or NOP Power-Down Entry
All Banks Idle AUTO REFRESH Self Refresh Entry
Reading or Writing VALID Clock Suspend Entry
H H See Truth Table 3

NOTE: 1. CKEn is the logic state of CKE at clock edge n; CKEn-1 was the state of CKE at the previous clock edge.
2. Current state is the state of the SDRAM immediately prior to clock edge n.
3. COMMANDn is the command registered at clock edge n, and ACTIONn is a result of COMMANDn.
4. All states and sequences not shown are illegal or reserved.
5. Exiting power-down at clock edge n will put the device in the all banks idle state in time for clock edge n + 1
(provided that tCKS is met).
6. Exiting self refresh at clock edge n will put the device in the all banks idle state once tXSR is met. COMMAND INHIBIT
or NOP commands should be issued on any clock edges occurring during the tXSR period. A minimum of two NOP
commands must be provided during tXSR period.
7. After exiting clock suspend at clock edge n, the device will resume operation and recognize the next command at
clock edge n + 1.

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TRUTH TABLE 3 – CURRENT STATE BANK n, COMMAND TO BANK n

(Notes: 1-6; notes appear below and on next page)

CURRENT STATE CS# RAS#CAS# WE# COMMAND (ACTION) NOTES

Any H X X X COMMAND INHIBIT (NOP/Continue previous operation)
L H H H NO OPERATION (NOP/Continue previous operation)
L L H H ACTIVE (Select and activate row)
Idle L L L H AUTO REFRESH 7
L L L L LOAD MODE REGISTER 7
L L H L PRECHARGE 11
L H L H READ (Select column and start READ burst) 10
Row Active L H L L WRITE (Select column and start WRITE burst) 10
L L H L PRECHARGE (Deactivate row in bank or banks) 8
Read L H L H READ (Select column and start new READ burst) 10
(Auto L H L L WRITE (Select column and start WRITE burst) 10
Precharge L L H L PRECHARGE (Truncate READ burst, start PRECHARGE) 8
Disabled) L H H L BURST TERMINATE 9
Write L H L H READ (Select column and start READ burst) 10
(Auto L H L L WRITE (Select column and start new WRITE burst) 10
Precharge L L H L PRECHARGE (Truncate WRITE burst, start PRECHARGE) 8
Disabled) L H H L BURST TERMINATE 9

NOTE: 1. This table applies when CKEn-1 was HIGH and CKEn is HIGH (see Truth Table 2) and after tXSR has been
met (if the previous state was self refresh).
2. This table is bank-specific, except where noted; i.e., the current state is for a specific bank and the commands shown
are those allowed to be issued to that bank when in that state. Exceptions are covered in the notes below.
3. Current state definitions:
Idle: The bank has been precharged, and tRP has been met.
Row Active: A row in the bank has been activated, and tRCD has been met. No data bursts/accesses
and no register accesses are in progress.
Read: A READ burst has been initiated, with auto precharge disabled, and has not yet
terminated or been terminated.
Write: A WRITE burst has been initiated, with auto precharge disabled, and has not yet
terminated or been terminated.
4. The following states must not be interrupted by a command issued to the same bank. COMMAND INHIBIT or NOP
commands, or allowable commands to the other bank should be issued on any clock edge occurring during these
states. Allowable commands to the other bank are determined by its current state and Truth Table 3, and according to
Truth Table 4.
Precharging: Starts with registration of a PRECHARGE command and ends when tRP is met. Once tRP is
met, the bank will be in the idle state.
Row Activating: Starts with registration of an ACTIVE command and ends when tRCD is met. Once tRCD is
met, the bank will be in the row active state.
Read w/Auto
Precharge Enabled: Starts with registration of a READ command with auto precharge enabled and ends
when tRP has been met. Once tRP is met, the bank will be in the idle state.
Write w/Auto
Precharge Enabled: Starts with registration of a WRITE command with auto precharge enabled and ends
when tRP has been met. Once tRP is met, the bank will be in the idle state.

(Continued on next page)

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SDRAM
NOTE (continued):
5. The following states must not be interrupted by any executable command; COMMAND INHIBIT or NOP commands
must be applied on each positive clock edge during these states.
Refreshing: Starts with registration of an AUTO REFRESH command and ends when tRC is met. Once
t
RC is met, the SDRAM will be in the all banks idle state.
Accessing Mode
Register: Starts with registration of a LOAD MODE REGISTER command and ends when tMRD has
been met. Once tMRD is met, the SDRAM will be in the all banks idle state.
Precharging All: Starts with registration of a PRECHARGE ALL command and ends when tRP is met. Once
t
RP is met, all banks will be in the idle state.
6. All states and sequences not shown are illegal or reserved.
7. Not bank-specific; requires that all banks are idle.
8. May or may not be bank-specific; if all banks are to be precharged, all must be in a valid state for precharging.
9. Not bank-specific; BURST TERMINATE affects the most recent READ or WRITE burst, regardless of bank.
10. READs or WRITEs listed in the Command (Action) column include READs or WRITEs with auto precharge enabled and
READs or WRITEs with auto precharge disabled.
11. Does not affect the state of the bank and acts as a NOP to that bank.

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TRUTH TABLE 4 – CURRENT STATE BANK n, COMMAND TO BANK m

(Notes: 1-6; notes appear below and on next page)

CURRENT STATE CS# RAS# CAS# WE# COMMAND (ACTION) NOTES

Any H X X X COMMAND INHIBIT (NOP/Continue previous operation)
L H H H NO OPERATION (NOP/Continue previous operation)
Idle X X X X Any Command Otherwise Allowed to Bank m
Row L L H H ACTIVE (Select and activate row)
Activating, L H L H READ (Select column and start READ burst) 7
Active, or L H L L WRITE (Select column and start WRITE burst) 7
Precharging L L H L PRECHARGE
Read L L H H ACTIVE (Select and activate row)
(Auto L H L H READ (Select column and start new READ burst) 7, 10
Precharge L H L L WRITE (Select column and start WRITE burst) 7, 11
Disabled) L L H L PRECHARGE 9
Write L L H H ACTIVE (Select and activate row)
(Auto L H L H READ (Select column and start READ burst) 7, 12
Precharge L H L L WRITE (Select column and start new WRITE burst) 7, 13
Disabled) L L H L PRECHARGE 9
Read L L H H ACTIVE (Select and activate row)
(With Auto L H L H READ (Select column and start new READ burst) 7, 8, 14
Precharge) L H L L WRITE (Select column and start WRITE burst) 7, 8, 15
L L H L PRECHARGE 9
Write L L H H ACTIVE (Select and activate row)
(With Auto L H L H READ (Select column and start READ burst) 7, 8, 16
Precharge) L H L L WRITE (Select column and start new WRITE burst) 7, 8, 17
L L H L PRECHARGE 9

NOTE: 1. This table applies when CKEn-1 was HIGH and CKEn is HIGH (see Truth Table 2) and after tXSR has been met (if the
previous state was self refresh).
2. This table describes alternate bank operation, except where noted; i.e., the current state is for bank n and the
commands shown are those allowed to be issued to bank m (assuming that bank m is in such a state that the given
command is allowable). Exceptions are covered in the notes below.
3. Current state definitions:
Idle: The bank has been precharged, and tRP has been met.
Row Active: A row in the bank has been activated, and tRCD has been met. No data bursts/accesses
and no register accesses are in progress.
Read: A READ burst has been initiated, with auto precharge disabled, and has not yet
terminated or been terminated.
Write: A WRITE burst has been initiated, with auto precharge disabled, and has not yet
terminated or been terminated.
Read w/Auto
Precharge Enabled: Starts with registration of a READ command with auto precharge enabled, and ends
when tRP has been met. Once tRP is met, the bank will be in the idle state.
Write w/Auto
Precharge Enabled: Starts with registration of a WRITE command with auto precharge enabled, and ends
when tRP has been met. Once tRP is met, the bank will be in the idle state.

(Continued on next page)

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NOTE (continued):
4. AUTO REFRESH, SELF REFRESH and LOAD MODE REGISTER commands may only be issued when all banks are idle.
5. A BURST TERMINATE command cannot be issued to another bank; it applies to the bank represented by the current
state only.
6. All states and sequences not shown are illegal or reserved.
7. READs or WRITEs to bank m listed in the Command (Action) column include READs or WRITEs with auto precharge
enabled and READs or WRITEs with auto precharge disabled.
8. CONCURRENT AUTO PRECHARGE: Bank n will initiate the AUTO PRECHARGE command when its burst has been
interrupted by bank m’s burst.
9. Burst in bank n continues as initiated.
10. For a READ without auto precharge interrupted by a READ (with or without auto precharge), the READ to bank m
will interrupt the READ on bank n, CAS latency later (Figure 7).
11. For a READ without auto precharge interrupted by a WRITE (with or without auto precharge), the WRITE to bank m
will interrupt the READ on bank n when registered (Figures 9 and 10). DQM should be used one clock prior to the
WRITE command to prevent bus contention.
12. For a WRITE without auto precharge interrupted by a READ (with or without auto precharge), the READ to bank m
will interrupt the WRITE on bank n when registered (Figure 17), with the data-out appearing CAS latency later. The
last valid WRITE to bank n will be data-in registered one clock prior to the READ to bank m.
13. For a WRITE without auto precharge interrupted by a WRITE (with or without auto precharge), the WRITE to bank m
will interrupt the WRITE on bank n when registered (Figure 15). The last valid WRITE to bank n will be data-in
registered one clock prior to the READ to bank m.
14. For a READ with auto precharge interrupted by a READ (with or without auto precharge), the READ to bank m will
interrupt the READ on bank n, CAS latency later. The PRECHARGE to bank n will begin when the READ to bank m is
registered (Figure 24).
15. For a READ with auto precharge interrupted by a WRITE (with or without auto precharge), the WRITE to bank m will
interrupt the READ on bank n when registered. DQM should be used two clocks prior to the WRITE command to
prevent bus contention. The PRECHARGE to bank n will begin when the WRITE to bank m is registered (Figure 25).
16. For a WRITE with auto precharge interrupted by a READ (with or without auto precharge), the READ to bank m will
interrupt the WRITE on bank n when registered, with the data-out appearing CAS latency later. The PRECHARGE to
bank n will begin after tWR is met, where tWR begins when the READ to bank m is registered. The last valid WRITE to
bank n will be data-in registered one clock prior to the READ to bank m (Figure 26).
17. For a WRITE with auto precharge interrupted by a WRITE (with or without auto precharge), the WRITE to bank m will
interrupt the WRITE on bank n when registered. The PRECHARGE to bank n will begin after tWR is met, where tWR
begins when the WRITE to bank m is registered. The last valid WRITE to bank n will be data registered one clock prior
to the WRITE to bank m (Figure 27).

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SDRAM

ABSOLUTE MAXIMUM RATINGS* *Stresses greater than those listed under “Absolute
Voltage on VDD, VDDQ Supply Maximum Ratings” may cause permanent damage to
Relative to VSS ....................................... -1V to +4.6V the device. This is a stress rating only, and functional
Voltage on Inputs, NC or I/O Pins operation of the device at these or any other conditions
Relative to VSS ....................................... -1V to +4.6V above those indicated in the operational sections of
Operating Temperature, this specification is not implied. Exposure to absolute
TA (commercial) ................................. 0°C to +70°C maximum rating conditions for extended periods may
Operating Temperature, affect reliability.
TA (industrial) .................................. -40°C to +85°C
Storage Temperature (plastic) ............ -55°C to +150°C
Power Dissipation ................................................... 1W

DC ELECTRICAL CHARACTERISTICS AND OPERATING CONDITIONS

(Notes: 1, 6; notes appear on page 35) (0°C ≤ TA ≤ +70°C; VDD, VDDQ = +3.3V ±0.3V)

PARAMETER/CONDITION SYMBOL MIN MAX UNITS NOTES

SUPPLY VOLTAGE VDD, VDDQ 3 3.6 V
INPUT HIGH VOLTAGE: Logic 1; All inputs VIH 2 VDD + 0.3 V 22
INPUT LOW VOLTAGE: Logic 0; All inputs VIL -0.3 0.8 V 22
INPUT LEAKAGE CURRENT:
Any input 0V ≤ VIN ≤ VDD II -5 5 µA
(All other pins not under test = 0V)
OUTPUT LEAKAGE CURRENT: DQs are disabled; 0V ≤ VOUT ≤ VDDQ IOZ -5 5 µA
OUTPUT LEVELS: VOH 2.4 – V
Output High Voltage (IOUT = -4mA)
Output Low Voltage (IOUT = 4mA) VOL – 0.4 V

IDD SPECIFICATIONS AND CONDITIONS

(Notes: 1, 6, 11, 13, 33; notes appear on page 35)
(0°C ≤ TA ≤ +70°C; VDD, VDDQ = +3.3V ±0.3V)
MAX
PARAMETER/CONDITION SYMBOL -7E -7G -75 -8E UNITS NOTES
OPERATING CURRENT: Active Mode; IDD1 125 125 115 95 mA 3, 18,
Burst = 2; READ or WRITE; tRC = tRC (MIN); CAS latency = 3 19, 32
STANDBY CURRENT: Power-Down Mode; All banks idle; IDD2 2 2 2 2 mA 32
CKE = LOW
STANDBY CURRENT: Active Mode; IDD3 45 45 45 35 mA 3, 12,
CKE = HIGH; CS# = HIGH; All banks active after tRCD met; 19, 32
No accesses in progress
OPERATING CURRENT: Burst Mode; Continuous burst; IDD4 150 150 140 120 mA 3, 18,
READ or WRITE; All banks active; CAS latency = 3 19, 32
AUTO REFRESH CURRENT: tRFC = tRFC (MIN); CL = 3 IDD5 230 230 210 190 mA 3, 12,
CKE = HIGH; CS# = HIGH 18, 19,
tRFC = 15.625µs; CL = 3 IDD6 3 3 3 3 mA 32, 34
SELF REFRESH CURRENT: Standard IDD7 1 1 1 1 mA 4
CKE ≤ 0.2V Low power (L) IDD7 0.5 0.5 0.5 0.5 mA

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SDRAM

CAPACITANCE
PARAMETER SYMBOL MIN MAX UNITS NOTES
Input Capacitance: CLK CI 1 2.5 3.5 pF 29
Input Capacitance: All other input-only pins C I2 2.5 3.8 pF 30
Input/Output Capacitance: DQs CIO 4.0 6.0 pF 31

ELECTRICAL CHARACTERISTICS AND RECOMMENDED AC OPERATING CONDITIONS

(Notes: 5, 6, 8, 9, 11, 33; notes appear on page 35) (0°C ≤ TA ≤ +70°C)

AC CHARACTERISTICS -7E -75 -7G -8E

PARAMETER SYMBOL MIN MAX MIN MAX MIN MAX MIN MAX UNITS NOTES
Access time from CLK (pos. edge) CL = 3 tAC 5.4 5.4 6 6 ns 27
CL = 2 tAC 5.4 6 – 6 ns
Address hold time tAH 0.8 0.8 1 1 ns
Address setup time tAS 1.5 1.5 2 2 ns
CLK high-level width tCH 2.5 2.5 2.75 3 ns
CLK low-level width tCL 2.5 2.5 2.75 3 ns
Clock cycle time CL = 3 tCK 7 7.5 7 8 ns 23
CL = 2 tCK 7.5 10 – 10 ns 23
CKE hold time tCKH 0.8 0.8 1 1 ns
CKE setup time tCKS 1.5 1.5 2 2 ns
CS#, RAS#, CAS#, WE#, DQM hold time tCMH 0.8 0.8 1 1 ns
CS#, RAS#, CAS#, WE#, DQM setup time tCMS 1.5 1.5 2 2 ns
Data-in hold time tDH 0.8 0.8 1 1 ns
Data-in setup time tDS 1.5 1.5 2 2 ns
Data-out high-impedance time CL = 3 tHZ 5.4 5.4 6 6 ns 10
CL = 2 tHZ 5.4 6 – 7 ns 10
Data-out low-impedance time tLZ 1 1 1 1 ns
Data-out hold time (load) tOH 2.7 2.7 2.5 3 ns
Data-out hold time (no load) tOH 1.8 1.8 1.8 1.8 ns 28
N
ACTIVE to PRECHARGE command tRAS 37 120,000 44 120,000 42 120,000 50 120,000 ns
ACTIVE to ACTIVE command period tRC 60 66 70 70 ns
ACTIVE to READ or WRITE delay tRCD 15 20 21 20 ns
Refresh period (4,096 rows) tREF 64 64 64 64 ms
AUTO REFRESH period tRFC 66 66 70 70 ns
PRECHARGE command period tRP 15 20 21 20 ns
ACTIVE bank a to ACTIVE bank b command tRRD 14 15 14 20 ns
Transition time tT 0.3 1.2 0.3 1.2 0.3 1.2 0.3 1.2 ns 7
WRITE recovery time tWR 1 CLK + 1 CLK + 1 CLK + 1 CLK + – 24
7ns 7.5ns 7ns 7ns
14 15 14 15 ns 25
Exit SELF REFRESH to ACTIVE command tXSR 67 75 77 80 ns

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 33 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

AC FUNCTIONAL CHARACTERISTICS
(Notes: 5, 6, 7, 8, 9, 11; notes appear on page 35) (0°C ≤ TA ≤ +70°C)

PARAMETER SYMBOL -7G -7E -7 -75 -8E UNITS NOTES

READ/WRITE command to READ/WRITE command tCCD 1 1 1 1 1 tCK 17
CKE to clock disable or power-down entry mode t CKED 1 1 1 1 1 tCK 14
CKE to clock enable or power-down exit setup mode tPED 1 1 1 1 1 tCK 14
DQM to input data delay t DQD 0 0 0 0 0 tCK 17
DQM to data mask during WRITEs tDQM 0 0 0 0 0 tCK 17
DQM to data high-impedance during READs tDQZ 2 2 2 2 2 tCK 17
WRITE command to input data delay t DWD 0 0 0 0 0 tCK 17
Data-in to ACTIVE command tDAL 5 4 4 5 4 tCK 15, 21
Data-in to PRECHARGE command tDPL 2 2 2 2 2 tCK 16, 21
Last data-in to burst STOP command t BDL 1 1 1 1 1 tCK 17
Last data-in to new READ/WRITE command tCDL 1 1 1 1 1 tCK 17
Last data-in to PRECHARGE command tRDL 2 2 2 2 2 tCK 16, 21
LOAD MODE REGISTER command to ACTIVE or REFRESH command t MRD 2 2 2 2 2 tCK 26
Data-out to high-impedance from PRECHARGE command CL = 3 tROH 3 3 3 3 3 tCK 17
CL = 2 tROH 2 2 2 2 2 tCK 17

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 34 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

NOTES
1. All voltages referenced to VSS. 14. Timing actually specified by tCKS; clock(s) speci-
2. This parameter is sampled. VDD, VDDQ = +3.3V; fied as a reference only at minimum cycle rate.
f = 1 MHz, TA = 25°C; pin under test biased at 1.4V. 15. Timing actually specified by tWR plus tRP; clock(s)
3. IDD is dependent on output loading and cycle rates. specified as a reference only at minimum cycle rate.
Specified values are obtained with minimum cycle 16. Timing actually specified by tWR.
time and the outputs open. 17. Required clocks are specified by JEDEC functional-
4. Enables on-chip refresh and address counters. ity and are not dependent on any timing param-
5. The minimum specifications are used only to eter.
indicate cycle time at which proper operation over 18. The IDD current will decrease as the CAS latency is
the full temperature range (0°C ≤ TA ≤ +70°C) is reduced. This is due to the fact that the maximum
ensured. cycle rate is slower as the CAS latency is reduced.
6. An initial pause of 100µs is required after power-up, 19. Address transitions average one transition every
followed by two AUTO REFRESH commands, be- two clocks.
fore proper device operation is ensured. (VDD and 20. CLK must be toggled a minimum of two times
VDDQ must be powered up simultaneously. VSS and during this period.
VSSQ must be at same potential.) The two AUTO 21. Based on tCK = 143 MHz for -7E/-7G, 133 MHz for
REFRESH command wake-ups should be repeated -75 and 100 MHz for -8E.
any time the tREF refresh requirement is exceeded. 22. VIH overshoot: VIH (MAX) = VDDQ + 2V for a pulse
7. AC characteristics assume tT = 1ns. width ≤ 3ns, and the pulse width cannot be greater
8. In addition to meeting the transition rate specifica- than one third of the cycle rate. VIL undershoot: VIL
tion, the clock and CKE must transit between VIH (MIN) = -2V for a pulse width ≤ 3ns.
and VIL (or between VIL and VIH) in a monotonic 23. The clock frequency must remain constant (stable
manner. clock is defined as a signal cycling within timing
9. Outputs measured at 1.5V with equivalent load: constraints specified for the clock pin) during ac-
cess or precharge states (READ, WRITE, including
Q tWR, and PRECHARGE commands). CKE may be

50pF used to reduce the data rate.

(-7G @ 30pF) 24. Auto precharge mode only. The precharge timing
budget (tRP) begins 7.5ns/7ns after the first clock
delay, after the last WRITE is executed.
10. tHZ defines the time at which the output achieves 25. Precharge mode only.
the open circuit condition; it is not a reference to 26. JEDEC and PC100 specify three clocks.
VOH or VOL. The last valid data element will meet 27. tAC for -7E/-75 at CL = 3 with no load is 4.6ns and
tOH before going High-Z. is guaranteed by design.
11. AC timing and IDD tests have VIL = 0V and VIH = 3V, 28. Parameter guaranteed by design.
with timing referenced to 1.5V crossover point. If 29. PC100 specifies a maximum of 4pF.
the input transition time is longer than 1ns, then 30. PC100 specifies a maximum of 5pF.
the timing is referenced at VIL (MAX) and VIL (MIN) 31. PC100 specifies a maximum of 6.5pF.
and no longer at the 1.5V crossover point. 32. tCK = 7ns for -7E/-7G, 7.5ns for -75 and 10ns
12. Other input signals are allowed to transition no for -8E.
more than once every two clocks and are otherwise 33. For -7G, VDD (MIN) = 3.15V, TA (MAX) = 55°C.
at valid VIH or VIL levels. 34. CKE is HIGH during refresh command period (tRFC
13. IDD specifications are tested after the device is [MIN]) else CKE is LOW. The IDD6 limit is actually
properly initialized. a nominal value and does not result in a fail value.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 35 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

INITIALIZE AND LOAD MODE REGISTER 1

T0 T1 Tn + 1 To + 1 Tp + 1 Tp + 2 Tp + 3
tCK (( (( tCL ((
CLK )) )) ))
(( (( tCH (( ((
)) )) )) ))
tCKS tCKH
(( (( (( ((
)) )) )) ))
CKE
(( ((
)) ))
tCMH tCMS tCMH tCMS tCMH tCMS
(( (( (( ((
)) )) AUTO )) AUTO )) LOAD MODE
COMMAND NOP PRECHARGE NOP NOP NOP NOP NOP ACTIVE
(( (( REFRESH (( REFRESH (( REGISTER
)) )) )) ))

(( (( (( ((
)) )) )) ))
DQM / ((
(( (( ((
DQML, DQMH )) )) )) ))

tAS tAH
(( (( (( ((
)) )) )) ))
A0-A9, A11 (( (( CODE ROW
(( ((
)) )) )) ))

tAS tAH
(( ALL BANKS (( (( ((
)) )) )) ))
A10 (( (( CODE ROW
(( ((
)) )) )) ))
SINGLE BANK

(( (( (( ((
)) ALL )) )) ))
BA0, BA1 (( BANK
(( BANKS (( ((
)) )) )) ))

(( High-Z ((
DQ
)) ))
T = 100µs
tRP tRFC tRFC tMRD
MIN

Power-up:
VDD and Precharge AUTO REFRESH AUTO REFRESH Program Mode Register 2, 3, 4
CLK stable all banks
DON’T CARE

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tCKS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tCMH 0.8 0.8 1 ns
tCH 2.5 2.5 3 ns tCMS 1.5 1.5 2 ns
tCL 2.5 2.5 3 ns tMRD3 2 2 2 tCK
tCK (3) 7 7.5 8 ns tRFC 66 66 70 ns
tCK (2) 7.5 10 10 ns tRP 15 20 20 ns
tCKH 0.8 0.8 1 ns

*CAS latency indicated in parentheses.

NOTE: 1. If CS# is HIGH at clock HIGH time, all commands applied are NOP, with CKE a “Don’t Care.”
2. The mode register may be loaded prior to the AUTO REFRESH cycles if desired.
3. JEDEC and PC100 specify three clocks.
4. Outputs are guaranteed High-Z after command is issued.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
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 64Mb: x4, x8, x16
SDRAM

POWER-DOWN MODE 1

T0 T1 T2 ((
Tn + 1 Tn + 2
tCK tCL ))
CLK
tCH ((
))
tCKS tCKS

CKE ((
))
tCKS tCKH

tCMS tCMH
((
))
COMMAND PRECHARGE NOP NOP NOP ACTIVE
((
))

((
DQM / ))
DQML, DQMH ((
))

((
))
A0-A9, A11 ROW
((
))

ALL BANKS ((
))
A10 ROW
((
SINGLE BANK ))

tAS tAH
((
))
BA0, BA1 BANK(S) BANK
((
))

High-Z
((
DQ ))
Two clock cycles Input buffers gated off while in
power-down mode
Precharge all All banks idle, enter All banks idle
active banks power-down mode Exit power-down mode

DON’T CARE

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tCK(2) 7.5 10 10 ns
tAS 1.5 1.5 2 ns tCKH 0.8 0.8 1 ns
tCH 2.5 2.5 3 ns tCKS 1.5 1.5 2 ns
tCL 2.5 2.5 3 ns tCMH 0.8 0.8 1 ns
tCK (3) 7 7.5 8 ns tCMS 1.5 1.5 2 ns

*CAS latency indicated in parentheses.

NOTE: 1. Violating refresh requirements during power-down may result in a loss of data.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 37 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

CLOCK SUSPEND MODE 1

T0 T1 T2 T3 T4 T5 T6 T7 T8 T9
tCK tCL
CLK
tCH

tCKS tCKH

CKE
tCKS tCKH

tCMS tCMH

COMMAND READ NOP NOP NOP NOP NOP WRITE NOP

tCMS tCMH
DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 COLUMN m 2 COLUMN e 2

tAS tAH

A10
tAS tAH

BA0, BA1 BANK BANK

tAC
tAC tOH tHZ tDS tDH

DQ tLZ
DOUT m DOUT m + 1 DOUT e DOUT e + 1

DON’T CARE

UNDEFINED

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAC (3) 5.4 5.4 6 ns tCKS 1.5 1.5 2 ns
tAC (2) 5.4 6 6 ns tCMH 0.8 0.8 1 ns
tAH 0.8 0.8 1 ns tCMS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tDH 0.8 0.8 1 ns
tCH 2.5 2.5 3 ns tDS 1.5 1.5 2 ns
tCL 2.5 2.5 3 ns tHZ (3) 5.4 5.4 6 ns
tCK(3) 7 7.5 8 ns tHZ (2) 5.4 6 7 ns
tCK(2) 7.5 10 10 ns tLZ 1 1 1 ns
tCKH 0.8 0.8 1 ns tOH 2.7 2.7 3 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 2, the CAS latency = 3, and auto precharge is disabled.
2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”

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64MSDRAM.p65 – Rev. 11/99 38 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

AUTO REFRESH MODE

T0 T1 T2 Tn + 1 To + 1
(( t CL ((
CLK )) ))
t CK t CH (( ((
)) ))
(( ((
)) ))
CKE

t CKS t CKH

t CMS t CMH
(( ((
AUTO )) AUTO ))
COMMAND PRECHARGE NOP NOP ACTIVE
REFRESH ( ( NOP REFRESH
NOP
( ( NOP
)) ))

(( ((
DQM / )) ))
DQML, DQMH (( ((
)) ))

(( ((
)) ))
A0-A9, A11 ROW
(( ((
)) ))

ALL BANKS (( ((
)) ))
A10 ROW
(( ((
SINGLE BANK )) ))

t AS t AH
(( ((
)) ))
BA0, BA1 BANK(S) BANK
(( ((
)) ))

DQ High-Z (( ((
)) ))
t RP t RFC1 t RFC1

Precharge all DON’T CARE

active banks

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tCKH 0.8 0.8 1 ns
tAS 1.5 1.5 2 ns tCKS 1.5 1.5 2 ns
tCH 2.5 2.5 3 ns tCMH 0.8 0.8 1 ns
tCL 2.5 2.5 3 ns tCMS 1.5 1.5 2 ns
tCK (3) 7 7.5 8 ns tRFC 66 66 70 ns
tCK (2) 7.5 10 10 ns tRP 15 20 20 ns

*CAS latency indicated in parentheses.

NOTE: 1. Each AUTO REFRESH command performs a refresh cycle. Back-to-back commands are not required.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 39 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

SELF REFRESH MODE

T0 T1 T2 ((
Tn + 1 ((
To + 1 To + 2
tCL )) ))
CLK
tCK tCH (( ((
tCKS )) ))
> tRAS
((
))
CKE (( ((
)) ))
tCKS tCKH tCKS

tCMS tCMH
(( ((
AUTO )) )) AUTO
COMMAND PRECHARGE NOP NOP ( (
REFRESH (( REFRESH
)) ))

(( ((
DQM / )) ))
DQML, DQMH (( ((
)) ))

(( ((
)) ))
A0-A11
(( ((
)) ))
ALL BANKS (( ((
)) ))
A10
(( ((
SINGLE BANK )) ))

tAS tAH
(( ((
)) ))
BA0, BA1 BANK(S) (( ((
)) ))

High-Z (( ((
DQ )) ))
tRP tXSR

Precharge all Enter self refresh mode Exit self refresh mode
active banks
(Restart refresh time base) DON’T CARE
CLK stable prior to exiting
self refresh mode

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tCKS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tCMH 0.8 0.8 1 ns
tCH 2.5 2.5 3 ns tCMS 1.5 1.5 2 ns
tCL 2.5 2.5 3 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCK (3) 7 7.5 8 ns tRP 15 20 20 ns
tCK (2) 7.5 10 10 ns tXSR 67 75 80 ns
tCKH 0.8 0.8 1 ns

*CAS latency indicated in parentheses.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 40 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

READ – WITHOUT AUTO PRECHARGE 1

T0 T1 T2 T3 T4 T5 T6 T7 T8
tCK tCL
CLK
tCH

tCKS tCKH

CKE
tCMS tCMH

COMMAND ACTIVE NOP READ NOP NOP NOP PRECHARGE NOP ACTIVE

tCMS tCMH
DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m2 ROW

tAS tAH
ALL BANKS
A10 ROW ROW

tAS tAH DISABLE AUTO PRECHARGE SINGLE BANKS

BA0, BA1 BANK BANK BANK(S) BANK

tAC tAC tAC

tAC tOH tOH tOH tOH

DQ DOUT m DOUT m+1 DOUT m+2 DOUT m+3

tLZ
tHZ
tRCD CAS Latency tRP
tRAS
tRC

DON’T CARE

UNDEFINED

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAC (3) 5.4 5.4 6 ns tCMH 0.8 0.8 1 ns
tAC (2) 5.4 6 6 ns tCMS 1.5 1.5 2 ns
tAH 0.8 0.8 1 ns tHZ (3) 5.4 5.4 6 ns
tAS 1.5 1.5 2 ns tHZ (2) 5.4 6 7 ns
tCH 2.5 2.5 3 ns tLZ 1 1 1 ns
tCL 2.5 2.5 3 ns tOH 2.7 2.7 3 ns
tCK (3) 7 7.5 8 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCK (2) 7.5 10 10 ns tRC 60 66 70 ns
tCKH 0.8 0.8 1 ns tRCD 15 20 20 ns
tCKS 1.5 1.5 2 ns tRP 15 20 20 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 4, the CAS latency = 2, and the READ burst is followed by a “manual”
PRECHARGE.
2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 41 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

READ – WITH AUTO PRECHARGE 1

T0 T1 T2 T3 T4 T5 T6 T7 T8
tCK tCL
CLK
tCH
tCKS tCKH

CKE

tCMS tCMH

COMMAND ACTIVE NOP READ NOP NOP NOP NOP NOP ACTIVE

tCMS tCMH
DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m 2 ROW

tAS tAH ENABLE AUTO PRECHARGE

A10 ROW ROW

tAS tAH

BA0, BA1 BANK BANK BANK

tAC tAC tAC

tAC tOH tOH tOH tOH

DQ DOUT m DOUT m + 1 DOUT m + 2 DOUT m + 3

tLZ
tHZ
tRCD CAS Latency tRP
tRAS
tRC

DON’T CARE
UNDEFINED

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAC (3) 5.4 5.4 6 ns tCMH 0.8 0.8 1 ns
tAC (2) 5.4 6 6 ns tCMS 1.5 1.5 2 ns
tAH 0.8 0.8 1 ns tHZ (3) 5.4 5.4 6 ns
tAS 1.5 1.5 2 ns tHZ (2) 5.4 6 7 ns
tCH 2.5 2.5 3 ns tLZ 1 1 1 ns
tCL 2.5 2.5 3 ns tOH 2.7 2.7 3 ns
tCK (3) 7 7.5 8 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCK (2) 7.5 10 10 ns tRC 60 66 70 ns
tCKH 0.8 0.8 1 ns tRCD 15 20 20 ns
tCKS 1.5 1.5 2 ns tRP 15 20 20 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 4, and the CAS latency = 2.
2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 42 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

SINGLE READ – WITHOUT AUTO PRECHARGE 1

T0 T1 T2 T3 T4 T5 T6 T7 T8
tCK tCL
CLK
tCH

tCKS tCKH

CKE
tCMS tCMH

COMMAND ACTIVE NOP READ NOP NOP3 PRECHARGE NOP ACTIVE NOP

tCMS tCMH
DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m2 ROW

tAS tAH
ALL BANKS
A10 ROW ROW

tAS tAH DISABLE AUTO PRECHARGE SINGLE BANKS

BA0, BA1 BANK BANK BANK(S) BANK

tAC tOH

DQ DOUT m
tLZ
tHZ
tRCD CAS Latency tRP
tRAS
tRC

DON’T CARE

UNDEFINED

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAC (3) 5.4 5.4 6 ns tCMH 0.8 0.8 1 ns
tAC (2) 5.4 6 6 ns tCMS 1.5 1.5 2 ns
tAH 0.8 0.8 1 ns tHZ (3) 5.4 5.4 6 ns
tAS 1.5 1.5 2 ns tHZ (2) 5.4 6 7 ns
tCH 2.5 2.5 3 ns tLZ 1 1 1 ns
tCL 2.5 2.5 3 ns tOH 2.7 2.7 3 ns
tCK (3) 7 7.5 8 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCK (2) 7.5 10 10 ns tRC 60 66 70 ns
tCKH 0.8 0.8 1 ns tRCD 15 20 20 ns
tCKS 1.5 1.5 2 ns tRP 15 20 20 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 1, the CAS latency = 2, and the READ burst is followed by a “manual”
PRECHARGE.
2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”
3. PRECHARGE command not allowed else tRAS would be violated.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 43 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

SINGLE READ – WITH AUTO PRECHARGE 1

T0 T1 T2 T3 T4 T5 T6 T7 T8
tCK tCL
CLK
tCH
tCKS tCKH

CKE

tCMS tCMH

COMMAND ACTIVE NOP NOP3 NOP3 READ NOP NOP ACTIVE NOP

tCMS tCMH
DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m2 ROW

tAS tAH ENABLE AUTO PRECHARGE

A10 ROW ROW

tAS tAH

BA0, BA1 BANK BANK BANK

tAC
t OH

DQ DOUT m
tRCD CAS Latency tHZ

tRAS tRP
tRC

DON T CARE
UNDEFINED

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAC (3) 5.4 5.4 6 ns tCMH 0.8 0.8 1 ns
tAC (2) 5.4 6 6 ns tCMS 1.5 1.5 2 ns
tAH 0.8 0.8 1 ns tHZ (3) 5.4 5.4 6 ns
tAS 1.5 1.5 2 ns tHZ (2) 5.4 6 7 ns
tCH 2.5 2.5 3 ns tLZ 1 1 1 ns
tCL 2.5 2.5 3 ns tOH 2.7 2.7 3 ns
tCK (3) 7 7.5 8 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCK (2) 7.5 10 10 ns tRC 60 66 70 ns
tCKH 0.8 0.8 1 ns tRCD 15 20 20 ns
tCKS 1.5 1.5 2 ns tRP 15 20 20 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 1, and the CAS latency = 2.
2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”
3. READ command not allowed else tRAS would be violated.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 44 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

ALTERNATING BANK READ ACCESSES 1

T0 T1 T2 T3 T4 T5 T6 T7 T8
tCK tCL
CLK
tCH
tCKS tCKH

CKE

tCMS tCMH

COMMAND ACTIVE NOP READ NOP ACTIVE NOP READ NOP ACTIVE

tCMS tCMH
DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m 2 ROW COLUMN b 2 ROW

tAS tAH ENABLE AUTO PRECHARGE ENABLE AUTO PRECHARGE

A10 ROW ROW ROW

tAS tAH

BA0, BA1 BANK 0 BANK 0 BANK 3 BANK 3 BANK 0

tAC tAC tAC tAC tAC

tAC tOH tOH tOH tOH tOH

DQ DOUT m DOUT m + 1 DOUT m + 2 DOUT m + 3 DOUT b

tLZ

tRCD - BANK 0 CAS Latency - BANK 0 tRP - BANK 0 tRCD - BANK 0

tRAS - BANK 0
tRC - BANK 0
tRRD tRCD - BANK 3 CAS Latency - BANK 3

DON’T CARE

UNDEFINED

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAC (3) 5.4 5.4 6 ns tCMH 0.8 0.8 1 ns
tAC (2) 5.4 6 6 ns tCMS 1.5 1.5 2 ns
tAH 0.8 0.8 1 ns tLZ 1 1 1 ns
tAS 1.5 1.5 2 ns tOH 2.7 2.7 3 ns
tCH 2.5 2.5 3 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCL 2.5 2.5 3 ns tRC 60 66 70 ns
tCK (3) 7 7.5 8 ns tRCD 15 20 20 ns
tCK (2) 7.5 10 10 ns tRP 15 20 20 ns
tCKH 0.8 0.8 1 ns tRRD 14 15 20 ns
tCKS 1.5 1.5 2 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 4, and the CAS latency = 2.
2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 45 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

READ – FULL-PAGE BURST 1

T0 T1 T2 T3 T4 T5 T6 ((
Tn + 1 Tn + 2 Tn + 3 Tn + 4
tCL tCK ))
CLK
tCH ((
))

tCKS tCKH
((
CKE ))
((
))
tCMS tCMH
((
))
COMMAND ACTIVE NOP READ NOP NOP NOP NOP NOP BURST TERM NOP NOP
((
))

tCMS tCMH
((
DQM / ))
DQML, DQMH ((
))

tAS tAH
((
))
A0-A9, A11 ROW COLUMN m 2 ((
))

tAS tAH
((
))
A10 ROW ((
))

tAS tAH
((
))
BA0, BA1 BANK BANK
((
))

tAC tAC tAC ( ( tAC tAC

tAC tOH tOH tOH ) ) tOH tOH tOH
((
))
DQ DOUT m DOUT m+1 DOUT m+2 DOUT m-1 DOUT m DOUT m+1
((
tLZ ))
tHZ
256 (x16) locations within same row
512 (x8) locations within same row
tRCD CAS Latency 1,024 (x4) locations within same row

DON’T CARE
Full page completed
UNDEFINED
Full-page burst does not self-terminate.
3
Can use BURST TERMINATE command.

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAC (3) 5.4 5.4 6 ns tCKS 1.5 1.5 2 ns
tAC (2) 5.4 6 6 ns tCMH 0.8 0.8 1 ns
tAH 0.8 0.8 1 ns tCMS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tHZ (3) 5.4 5.4 6 ns
tCH 2.5 2.5 3 ns tHZ (2) 5.4 6 7 ns
tCL 2.5 2.5 3 ns tLZ 1 1 1 ns
tCK(3) 7 7.5 8 ns tOH 2.7 2.7 3 ns
tCK(2) 7.5 10 10 ns tRCD 15 20 20 ns
tCKH 0.8 0.8 1 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the CAS latency = 2.

2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”
3. Page left open; no tRP.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 46 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

READ – DQM OPERATION 1

T0 T1 T2 T3 T4 T5 T6 T7 T8
tCK tCL
CLK
tCH
tCKS tCKH

CKE
tCMS tCMH

COMMAND ACTIVE NOP READ NOP NOP NOP NOP NOP NOP

tCMS tCMH

DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m 2

tAS tAH
ENABLE AUTO PRECHARGE
A10 ROW
DISABLE AUTO PRECHARGE
tAS tAH

BA0, BA1 BANK BANK

tAC
tAC tOH tAC tOH tOH

DQ DOUT m DOUT m + 2 DOUT m + 3

tLZ
tHZ tLZ tHZ

tRCD CAS Latency

DON’T CARE

UNDEFINED

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAC (3) 5.4 5.4 6 ns tCKS 1.5 1.5 2 ns
tAC (2) 5.4 6 6 ns tCMH 0.8 0.8 1 ns
tAH 0.8 0.8 1 ns tCMS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tHZ (3) 5.4 5.4 6 ns
tCH 2.5 2.5 3 ns tHZ (2) 5.4 6 7 ns
tCL 2.5 2.5 3 ns tLZ 1 1 1 ns
tCK (3) 7 7.5 8 ns tOH 2.7 2.7 3 ns
tCK(2) 7.5 10 10 ns tRCD 15 20 20 ns
tCKH 0.8 0.8 1 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 4, and the CAS latency = 2.
2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 47 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

WRITE – WITHOUT AUTO PRECHARGE 1

T0 T1 T2 T3 T4 T5 T6 T7 T8
tCK tCL
CLK
tCH
tCKS tCKH

CKE

tCMS tCMH

COMMAND ACTIVE NOP WRITE NOP NOP NOP PRECHARGE NOP ACTIVE

tCMS tCMH

DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m 3 ROW

tAS tAH
ALL BANKS

A10 ROW ROW

DISABLE AUTO PRECHARGE SINGLE BANK
tAS tAH

BA0, BA1 BANK BANK BANK BANK

tDS tDH tDS tDH tDS tDH tDS tDH

DQ DIN m DIN m + 1 DIN m + 2 DIN m + 3

tRCD t WR 2 tRP
tRAS
tRC

DON’T CARE

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tCMS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tDH 0.8 0.8 1 ns
tCH 2.5 2.5 3 ns tDS 1.5 1.5 2 ns
tCL 2.5 2.5 3 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCK(3) 7 7.5 8 ns tRC 60 66 70 ns
tCK(2) 7.5 10 10 ns tRCD 15 20 20 ns
tCKH 0.8 0.8 1 ns tRP 15 20 20 ns
tCKS 1.5 1.5 2 ns tWR 14 15 15 ns
tCMH 0.8 0.8 1 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 4, and the WRITE burst is followed by a “manual” PRECHARGE.
2. 15ns is required between <DIN m> and the PRECHARGE command, regardless of frequency.
3. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 48 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

WRITE – WITH AUTO PRECHARGE 1

T0 T1 T2 T3 T4 T5 T6 T7 T8 T9
tCK tCL
CLK
tCH
tCKS tCKH

CKE

tCMS tCMH

COMMAND ACTIVE NOP WRITE NOP NOP NOP NOP NOP NOP ACTIVE

tCMS tCMH
DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m 2 ROW

tAS tAH
ENABLE AUTO PRECHARGE

A10 ROW ROW

tAS tAH

BA0, BA1 BANK BANK BANK

tDS tDH tDS tDH tDS tDH tDS tDH

DQ DIN m DIN m + 1 DIN m + 2 DIN m + 3

tRCD tWR tRP
tRAS
tRC

DON’T CARE

TIMING PARAMETERS

-7E -75 -8E 7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tCMS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tDH 0.8 0.8 1 ns
tCH 2.5 2.5 3 ns tDS 1.5 1.5 2 ns
tCL 2.5 2.5 3 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCK (3) 7 7.5 8 ns tRC 60 66 70 ns
tCK (2) 7.5 10 10 ns tRCD 15 20 20 ns
tCKH 0.8 0.8 1 ns tRP 15 20 20 ns
tCKS 1.5 1.5 2 ns tWR 1 CLK + 1 CLK + 1 CLK + –
tCMH 0.8 0.8 1 ns 7ns 7.5ns 7ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 4.

2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 49 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

SINGLE WRITE – WITHOUT AUTO PRECHARGE 1

T0 T1 T2 T3 T4 T5 T6 T7 T8
tCK tCL
CLK
tCH
tCKS tCKH

CKE

tCMS tCMH

COMMAND ACTIVE NOP WRITE NOP 4 NOP 4 PRECHARGE NOP ACTIVE NOP

tCMS tCMH

DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m 3 ROW

tAS tAH
ALL BANKS

A10 ROW ROW

DISABLE AUTO PRECHARGE SINGLE BANK
tAS tAH

BA0, BA1 BANK BANK BANK BANK

tDS tDH

DQ DIN m
tRCD t WR 2 tRP
tRAS
tRC

DON’T CARE

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tCMS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tDH 0.8 0.8 1 ns
tCH 2.5 2.5 3 ns tDS 1.5 1.5 2 ns
tCL 2.5 2.5 3 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCK (3) 7 7.5 8 ns tRC 60 66 70 ns
tCK(2) 7.5 10 10 ns tRCD 15 20 20 ns
tCKH 0.8 0.8 1 ns tRP 15 20 20 ns
tCKS 1.5 1.5 2 ns tWR 14 15 15 ns
tCMH 0.8 0.8 1 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 1, and the WRITE burst is followed by a “manual” PRECHARGE.
2. 15ns is required between <DIN m> and the PRECHARGE command, regardless of frequency.
3. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”
4. PRECHARGE command not allowed else tRAS would be violated.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 50 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

SINGLE WRITE – WITH AUTO PRECHARGE 1

T0 T1 T2 T3 T4 T5 T6 T7 T8 T9
tCK tCL
CLK
tCH
tCKS tCKH

CKE

tCMS tCMH

COMMAND ACTIVE NOP3 NOP3 NOP3 WRITE NOP NOP NOP ACTIVE NOP

tCMS tCMH
DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m 2 ROW

tAS tAH
ENABLE AUTO PRECHARGE

A10 ROW ROW

tAS tAH

BA0, BA1 BANK BANK BANK

tDS tDH

DQ DIN m
tRCD tWR tRP
tRAS
tRC

DON’T CARE

TIMING PARAMETERS

-7E -75 -8E 7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tCMS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tDH 0.8 0.8 1 ns
tCH 2.5 2.5 3 ns tDS 1.5 1.5 2 ns
tCL 2.5 2.5 3 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCK (3) 7 7.5 8 ns tRC 60 66 70 ns
tCK (2) 7.5 10 10 ns tRCD 15 20 20 ns
tCKH 0.8 0.8 1 ns tRP 15 20 20 ns
tCKS 1.5 1.5 2 ns tWR 1 CLK + 1 CLK + 1 CLK + –
tCMH 0.8 0.8 1 ns 7ns 7.5ns 7ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 1.

2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”
3. WRITE command not allowed else tRAS would be violated.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 51 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

ALTERNATING BANK WRITE ACCESSES 1

T0 T1 T2 T3 T4 T5 T6 T7 T8 T9
tCK tCL
CLK
tCH
tCKS tCKH

CKE

tCMS tCMH

COMMAND ACTIVE NOP WRITE NOP ACTIVE NOP WRITE NOP NOP ACTIVE

tCMS tCMH
DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m 2 ROW COLUMN b 2 ROW

tAS tAH ENABLE AUTO PRECHARGE ENABLE AUTO PRECHARGE

A10 ROW ROW ROW

tAS tAH

BA0, BA1 BANK 0 BANK 0 BANK 1 BANK 1 BANK 0

tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH

DQ DIN m DIN m + 1 DIN m + 2 DIN m + 3 DIN b DIN b + 1 DIN b + 2 DIN b + 3

tRCD - BANK 0 tWR - BANK 0 tRP - BANK 0 tRCD - BANK 0

tRAS - BANK 0
tRC - BANK 0
tRRD tRCD - BANK 1 tWR - BANK 1

DON’T CARE

TIMING PARAMETERS

7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tDH 0.8 0.8 1 ns
tAS 1.5 1.5 2 ns tDS 1.5 1.5 2 ns
tCH 2.5 2.5 3 ns tRAS 37 120,000 44 120,000 50 120,000 ns
tCL 2.5 2.5 3 ns tRC 60 66 70 ns
tCK (3) 7 7.5 8 ns tRCD 15 20 20 ns
tCK(2) 7.5 10 10 ns tRP 15 20 20 ns
tCKH 0.8 0.8 1 ns tRRD 14 15 20 ns
tCKS 1.5 1.5 2 ns tWR 1 CLK + 1 CLK + 1 CLK + –
tCMH 0.8 0.8 1 ns 7ns 7.5ns 7ns
tCMS 1.5 1.5 2 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 4.

2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 52 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

WRITE – FULL-PAGE BURST

T0 T1 T2 T3 T4 T5 ((
Tn + 1 Tn + 2 Tn + 3
tCL tCK ))
CLK
tCH ((
))

tCKS tCKH
((
))
CKE
((
))
tCMS tCMH
((
))
COMMAND ACTIVE NOP WRITE NOP NOP NOP NOP BURST TERM NOP
((
))

tCMS tCMH
((
DQM / ))
DQML, DQMH ((
))

tAS tAH
((
))
A0-A9, A11 ROW COLUMN m 1
((
))

tAS tAH
((
))
A10 ROW ((
))

tAS tAH
((
))
BA0, BA1 BANK BANK
((
))

tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH tDS tDH
((
))
DQ DIN m DIN m + 1 DIN m + 2 DIN m + 3 (( DIN m - 1
))
tRCD
Full-page burst does
256 (x16) locations within same row not self-terminate. Can
512 (x8) locations within same row use BURST TERMINATE
1,024 (x4) locations within same row command to stop.2, 3

Full page completed DON’T CARE

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tCKS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tCMH 0.8 0.8 1 ns
tCH 2.5 2.5 3 ns tCMS 1.5 1.5 2 ns
tCL 2.5 2.5 3 ns tDH 0.8 0.8 1 ns
tCK (3) 7 7.5 8 ns tDS 1.5 1.5 2 ns
tCK(2) 7.5 10 10 ns tRCD 15 20 20 ns
tCKH 0.8 0.8 1 ns

*CAS latency indicated in parentheses.

NOTE: 1. x16: A8, A9 and A11 = “Don’t Care”

x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”
2. tWR must be satisfied prior to PRECHARGE command.
3. Page left open; no tRP.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 53 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

WRITE – DQM OPERATION 1

T0 T1 T2 T3 T4 T5 T6 T7
tCK tCL
CLK
tCH
tCKS tCKH

CKE

tCMS tCMH

COMMAND ACTIVE NOP WRITE NOP NOP NOP NOP NOP

tCMS tCMH
DQM /
DQML, DQMH
tAS tAH

A0-A9, A11 ROW COLUMN m 2

tAS tAH
ENABLE AUTO PRECHARGE
A10 ROW
tAS tAH DISABLE AUTO PRECHARGE

BA0, BA1 BANK BANK

tDS tDH tDS tDH tDS tDH

DQ DIN m DIN m + 2 DIN m + 3

tRCD
DON’T CARE

TIMING PARAMETERS

-7E -75 -8E -7E -75 -8E

SYMBOL* MIN MAX MIN MAX MIN MAX UNITS SYMBOL* MIN MAX MIN MAX MIN MAX UNITS
tAH 0.8 0.8 1 ns tCKS 1.5 1.5 2 ns
tAS 1.5 1.5 2 ns tCMH 0.8 0.8 1 ns
tCH 2.5 2.5 3 ns tCMS 1.5 1.5 2 ns
tCL 2.5 2.5 3 ns tDH 0.8 0.8 1 ns
tCK (3) 7 7.5 8 ns tDS 1.5 1.5 2 ns
tCK (2) 7.5 10 10 ns tRCD 15 20 20 ns
tCKH 0.8 0.8 1 ns

*CAS latency indicated in parentheses.

NOTE: 1. For this example, the burst length = 4.

2. x16: A8, A9 and A11 = “Don’t Care”
x8: A9 and A11 = “Don’t Care”
x4: A11 = “Don’t Care”

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 54 ©1999, Micron Technology, Inc.
 64Mb: x4, x8, x16
SDRAM

54-PIN PLASTIC TSOP (400 mil)

22.30 3 SEE DETAIL A

22.14 4
.71
.80 TYP
.10 (2X)
.45
.30

9 9 2.80
11.86 5
11.66 6
PIN #1 ID 7
10.24
10.08 8

.75 (2X)
.18
.13
1.00 (2X) .25

.20
.05
.10 .60
.40
1.2 MAX
.80
TYP

DETAIL A

NOTE: 1. All dimensions in millimeters MAX or typical where noted.

MIN
2. Package width and length do not include mold protrusion; allowable mold protrusion is 0.25mm per side.
3. 22.35 for some versions.
4. 22.09 for some versions.
5. 11.96 for some versions.
6. 11.56 for some versions.
7. 10.29 for some versions.
8. 10.03 for some versions.

8000 S. Federal Way, P.O. Box 6, Boise, ID 83707-0006, Tel: 208-368-3900

E-mail: prodmktg@micron.com, Internet: http://www.micron.com, Customer Comment Line: 800-932-4992
Micron is a registered trademark of Micron Technology, Inc.

64Mb: x4, x8, x16 SDRAM Micron Technology, Inc., reserves the right to change products or specifications without notice.
64MSDRAM.p65 – Rev. 11/99 55 ©1999, Micron Technology, Inc.