Special circuit for LED drive control TM1639

一、 Introduction

TM1639 is an IC dedicated to LED (light emitting diode display) drive control and equipped with a
keypad scan interface. It integrates MCU digital interface, data latch, LED drive, and keypad scanning
circuit. This product is reliable in quality, stable in performance and strong in interference resistance. It
is mainly used for household electrical appliances (smart water heaters, microwave ovens, washing
machines, air conditioners, electric stove), set-top boxes, electronic scale, smart meters and other Nixie
tube or LED display devices.

二、Features

• CMOS technology
• 8 segments × 8 bits display
• Keypad scanning (4 × 2 bits)
• Brightness adjustment circuit (8-level adjustable duty ratio)
• Serial ports (CLK, STB, DIO)
• Oscillation mode: RC oscillation
• Built-in power-on reset circuit
• Package type: SOP24，SDIP24

三、Pin definition：
GRID4 1 24 GRID5
GRID3 2 23 GRID6
GND 3 22 GND
GRID2 4 21 GRID7
GRID1 5 20 GRID8
DIO 6 19 SEG12
CLK 7 TM1639 18 SEG11
STB 8 (TOP VIEW) 17 SEG10
K0 9 16 SEG9
K1 10 15 KS4/SEG4
VDD 11 14 KS3/SEG3
SEG1/KS1 12 13 KS2/SEG2

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 Special circuit for LED drive control TM1639
四、Pin function：
Symbol Pin Name Pin ID Description

Input serial data at rising edge of the

clock, starting from lower bits. Output
Data input and
DIO 6 serial data at falling edge of the clock,
output
starting from lower bits. During output,
this is a PMOS open drain output.

Read serial data at rising edge and

CLK Clock input 7
output data at falling edge.

Initialize the serial interface at falling

edge, then wait to receive instructions.
The first byte after STB becomes low is
Chip selection
STB 8 considered as an instruction. When an
input
instruction is being processed, other
current processes are terminated. When
STB is high, CLK is ignored.
keypad The data input into this pin is latched at
K0～K1 scanning signal 9～10 the end of display cycle
input
Segment output (also used as keypad
SGE1/KS1～ Output
12～15 scanning output). This is a PMOS
SEG4/KS4 (segment)
open-drain output

1～5 Grid output. This is an NMOS

GRID1～GRID8 Output (bit)
20～24 open-drain output.

Output Segment output. This is a PMOS open

SEG9 ～SEG12 16～19
(segment) drain output.

VDD Logic Supply 11 Positive Power Supply

GND Logic GND 3，22 System Ground

▲ Note: When DIO outputs data, it is an NMOS open drain output, To read the keypad, an external pull-up resistor
should be provided to connect 1K-10K . The Company recommends a 10K pullup resistor. At falling edge of the
clock, DIO controls the operation of NMOS, at which point, the reading is unstable until rising edge of the clock.

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 Special circuit for LED drive control TM1639
五、Description of Instructions：
The first byte input by DIO after the falling edge of STB is considered as an instruction. After decoding, obtain the
topmost B7 and B6 bits to distinguish different instructions.
B7 B6 Instruction
0 1 Setting of Data Command
Setting of Display Control
1 0
Command
1 1 Setting of Address Command
If STB is set high during instruction or data transmission, serial communication is initialized, and the instruction
or data being transmitted is invalid (but the instruction or data transmitted before remains active.)

5． 1 Setting of Data Command

This instruction is used to set data writing and reading. Bits B1 and B0 cannot set to 01 or 11.
MSB LSB
B7 B6 B5 B4 B3 B2 B1 B0 Function Description
Write data to the
0 1 0 0 Setting of data display register
read-write mode
0 1 1 0 Read key scanning data
0 1 Unrelated 0 Set address Auto increment
0 1 item, fill 0 1 increment mode Fixed address
0 1 0 Test mode Normal mode
setting (for
0 1 1 internal use) Test mode

5． 2 Setting of Address Command

MSB LSB
B7 B6 B5 B4 B3 B2 B1 B0 Display address
1 1 0 0 0 0 00H
1 1 0 0 0 1 01H
1 1 0 0 1 0 02H
1 1 0 0 1 1 03H
1 1 0 1 0 0 04H
1 1 0 1 0 1 05H
1 1 0 1 1 0 06H
1 1 Unrelated 0 1 1 1 07H
1 1 item, fill 0 1 0 0 0 08H
1 1 1 0 0 1 09H
1 1 1 0 1 0 0AH
1 1 1 0 1 1 0BH
1 1 1 1 0 0 0CH
1 1 1 1 0 1 0DH
1 1 1 1 1 0 0EH
1 1 1 1 1 1 0FH
If the address is 10H or higher, data will be ignored until a valid address is set. On power-up, the address is
set to 00H by default.

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 Special circuit for LED drive control TM1639
5． 3 Display control
MSB LSB
B7 B6 B5 B4 B3 B2 B1 B0 Function Description
1 0 0 0 0 the pulse width to 1/16
1 0 0 0 1 the pulse width to 2/16
1 0 0 1 0 the pulse width to 4/16
Set the pulse width to
1 0 0 1 1
10/16
Set the Set the pulse width to
1 0 1 0 0 number of 11/16
Unrelated extinction
item, fill 0 Set the pulse width to
1 0 1 0 1
12/16
Set the pulse width to
1 0 1 1 0
13/16
Set the pulse width to
1 0 1 1 1
14/16
1 0 0 Setting of Display Off
1 0 1 display switch Display ON

六、Address of display register:

The register stores data transmitted through the serial interface from an external device to TM1639, or, to the
address of 16 bytes ranging from 00H-0FH, each corresponding to the LEDs connected with the chip SEG and GRID
pins, as assigned below:
LED display data are written in an ascending order of both display address and data byte.
SEG10

SEG12
SEG11
SEG1

SEG2

SEG3

SEG4

SEG9

X X X X X X X X

xxHL (low four) xxHU (high four) xxHL (low four) xxHU (high four)
B0 B1 B2 B3 B4 B5 B6 B7 B0 B1 B2 B3 B4 B5 B6 B7
00HL 00HU 01HL 01HU GRID1
02HL 02HU 03HL 03HU GRID2
04HL 04HU 05HL 05HU GRID3
06HL 06HU 07HL 07HU GRID4
08HL 08HU 09HL 09HU GRID5
0AHL 0AHU 0BHL 0BHU GRID6
0CHL 0CHU 0DHL 0DHU GRID7
0EHL 0EHU 0FHL 0FHU GRID8
Figure (2)
▲Note: The moment the display register of the chip is powered on, the values stored inside may be random, at which
point, customers may directly send a command to turn on the screen.Messy codes are likely to appear. Considering
that, the company advise customers to clear the display register upon power-on, i.e., writing 0x00 into all the 16-byte
memory addresses (00H-0FH).

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 Special circuit for LED drive control TM1639
七、Display
1、Driving common cathode LEDs:
SEG1

SEG2
SEG1 a
SEG3 SEG2 b a
SEG3 c f b
SEG4 g GRID1
SEG4 GRID1 d com
SEG5 ee c
SEG5 SEG6 f d
SEG7 dp
g
SEG8 dp
SEG6

SEG7

SEG8

Figure (7)
Figure 7 is a diagram for the wiring of common cathode LEDs. To display 0 off the LED segment display,
customers only need to write 0x3F to the 00H (GRID1) address starting from lower bits, at which point, 00H
corresponds to the data in SEG1-SEG8 as shown in the table below.
SEG8 SEG7 SEG6 SEG5 SEG4 SEG3 SEG2 SEG1
0 0 1 1 1 1 1 1 GRID1(00H)
B7 B6 B5 B4 B3 B2 B1 B0

2、Driving common anode LEDs：

GRID1

GRID2
GRID1 a
GRID3 GRID2 b a
GRID3 c f b
GRID4 g SEG1
SEG1 GRID4 d com
GRID5 ee c
GRID5 GRID6 f d
GRID7 g dp

GRID6 GRID8 dp

GRID7

GRID8

Figure (8)
Figure 8 is a diagram for the wiring of common anode LEDs. To display 0 off the LED segment display, customers
only need to write O1H into 00H (GRID1), 02H (GRID2), 04H (GRID3), 06H (GRID4), 08H (GRID5),and 0AH
(GRID6), and 00H into 0CH (GRID7) and 0EH (GRID8). SEG1-SEG8 correspond to the data table below.

SEG8 SEG7 SEG6 SEG5 SEG4 SEG3 SEG2 SEG1

0 0 0 0 0 0 0 1 GRID1(00H)
0 0 0 0 0 0 0 1 GRID2(02H)
0 0 0 0 0 0 0 1 GRID3(04H)
0 0 0 0 0 0 0 1 GRID4(06H)
0 0 0 0 0 0 0 1 GRID5(08H)
0 0 0 0 0 0 0 1 GRID6(0AH)
0 0 0 0 0 0 0 0 GRID7(0CH)

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 Special circuit for LED drive control TM1639
0 0 0 0 0 0 0 0 GRID8(0EH)
B7 B6 B5 B4 B3 B2 B1 B0

▲Note: To drive common cathode LEDs or common anode LEDs, SEG pins can only be connected with LED anode,
and GRID, only with LED cathode. Do not connect them in reverse direction.

八、Key scanning and key combination：

The key scanning matrix is 4 × 2 bit, as shown in Figure (3) below:

K0

K1
KS1

KS2

KS3

KS4

Figure (3)
The storage address for keypad data is shown in (4). Upon a key reading command, the device starts to read key
data BYTE1-BYTE2. Data already read will be output starting from lower bits. When a key corresponding to a pin of
chips K and KS is pressed , the BIT corresponding to the byte is 1.
B0 B1 B2 B3 B4 B5 B6 B7
X X K1 K0 X X K1 K0
KS1 KS2 BYTE1
KS3 KS4 BYTE2
Figure (4)
▲Data are read in order from BYTE1to BYTE2 without skipping any byte. For example: When the key corresponding
to K1 and KS4 is pressed, it is impossible to know the data unless and until the data from the key is read down to the
sixth BIT of the second byte. When two keys corresponding to K1 and KS8 as well as K2 and KS8 respectively are
pressed simultaneously, B6 and B7 of the data read from BYTE4 are both 1.
3、A combination key can only be formed on the same KS pins and different K pins. It is impossible to from a
combination key on the same K pin but different KS pins.

Keypad scan and combination keys:

（1）Keypad scan: keypad scanning is automatically done by TM1638 without user control. User only need to
read key codes according to time sequence. It takes a display cycle to scan keypad and a display cycle takes about T =
4.7ms. During this 4.7ms, if two different keys are pressed, the key code read in both times is the one of the key
pressed first.
（2）Combination keys
Unusual problems with combination keys: SEG1/KS1-SEG8/KS8 are for combined use for display and keypad
scanning. Take Figure (12) for example,to turn D1 on and D2 off, we have make sure SEG1 is in the status of “0” and
SEG2, the status of “1”. If S1 and S2 are pressed simultaneously, it is to the effect that SEG1 and SEG2 are
short-circuited, then D1 and D2 are turned on.

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 Special circuit for LED drive control TM1639

SGE1/KS1 S1

SGE2/KS2 S2

D1 D2

K1
GRID1

Figure (12)
Solution:
1、 In terms of hardware, it is advisable to arrange the keys to be pressed at the same time on different K line,
as shown in Fgire (13).
SGE1/KS1
S1
D1 D2
1

1
S2

GRID1 GRID2 K1 K2
Figure (13)

2、Series diodes are shown in Figure (14).

SGE1/KS1
S1

SGE2/KS2
S2

D1 D2
1

K1
GRID1
Figure (14)

▲Note: It is recommend to form combination keys on the same KS but different KS.

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 Special circuit for LED drive control TM1639
九、Transmission format of serial data:
A BIT is read and received at rising edge of the clock.

Data reception (write data)

CLK

DIO B0 B1 B2 B3 B4 B5 B6 B7

STB
Figure (5)
Data reading (read data)

CLK

DIO B0 B1 B2 B3 B4 B5 B6 B7 B0 B1 B2 B3 B4

STB

Date Read Command is set Twait Date Reading Starts

Figure (6)
▲Note: 1. When data is read, it takes a waiting time Twait (minimum 2μS) from instruction setting at the eighth
rising edge of the serial clock CLK to data reading at falling edge of the CLK. See the Timing
Characteristics table for specific parameters.

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 Special circuit for LED drive control TM1639
十、Transmission of serial data in application
（1）Address increment mode
If address automatically increments by 1, the essence of address setting is to set the starting address where a data
stream transmitted is stored. After the command word of the Starting Address has been sent, “STB” does not need to be
set high to transmit data immediately thereafter, given 16 BYTEs at most. It is advisable to set STB high after data
transmission.
CLK

DIO Command1 Command2 Data1 Data2 ``````` Data n Command3

STB

Command1: Set data command

Command2: Set display address
Data1～n: Transmit display data to the Command3 address and the following addresses (16 bytes at most)
Command3: Set display control command

（2）Fixed Address Mode

If fixed address mode is adopted, the essence of address setting is to set the address where 1 BYTE data to be
transmitted is stored. After transmission of address, it is not necessary to set “STB” high to transmit 1BYTE data
immediately thereafter. It is advisable to set STB high after data transmission. Then users may set the address where the
second data is stored. After transmission of date up to 16 BYTES at most, “STB” is set high.
CLK

DIO Command1 Command2 Data1 Command3 Data2 ``````` Command4

STB

Command1: Set data command

Command2: Set display address1
Data1: Transmit display data 1 to Command3 address
Command3: et display address2
Data2: Transmit display data 2 to Command4 address
Command4: Set display control command

（3）Timing for key reading

CLK

DIO Command1 Data1 Data2

STB
Command1: Set key reading command
Data1 ~ 2: read key data

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 Special circuit for LED drive control TM1639
（4）Flowchart for program design in the modes of auto address increment by 1 and fixed address:
Flowchart for program design in the mode of auto address increment by 1:

Start

Set data commend for

key reading (42H)
Initialization

No
Read the contents
of 1 byte
Set command for writing data
into display memory, in the
mode of auto address increment
by 1(40H)
Save the key value
into the register of
MCU

Set starting
Address 0xc0

No Have 2 bytes
been read?
Transmit
data

Yes

Is any key pressed?

Have the 16-byte

Data been Transmitted?
Yes

Key
Yes

processing
No

Transmit the display

control command to set
maximum brightness (8FH)
End

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 Special circuit for LED drive control TM1639
Flowchart for program design in the mode of fixed address:

Start
Transmit the display control
command to set maximum
brightness (8FH)

Initialization
Set data commend
设
for key reading 42H

Set command for writing data No

into display memory, in the Read the
mode of fixed address (44H) contents of 1
byte

Save the key value

Set Starting into the register of
address C0H MCU

Transmit 1
byte data Have 2 bytes been
Read?
Yes

Set a new
address 0C1H

Is any key pressed?

Transmit 1
byte data

Key processing
……Transit program
the rest data

End

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 Special circuit for LED drive control TM1639
十一． Application Circuit：
Hardware circuit diagram for TM1639 to drive a common cathode LED screen
SEG1 a SEG1 a SEG1 a SEG1 a
a a a a
SEG2 b SEG2 b SEG2 b SEG2 b
SEG3 c f b SEG3 c f b SEG3 c f b SEG3 c f b
g GRID8 g GRID7 g GRID6 g
SEG4 d SEG4 d SEG4 d SEG4 d GRID5
SEG9 ee c SEG9 ee c SEG9 ee c SEG9 ee c
d d d d
SEG10 f SEG10 f SEG10 f SEG10 f
dp dp dp dp
SEG11 g SEG11 g SEG11 g SEG11 g
SEG12 SEG12 SEG12 dp SEG12
dp dp dp

SEG1 a SEG1 a SEG1 a SEG1 a

a a a a
SEG2 b SEG2 b SEG2 b SEG2 b
SEG3 c f b SEG3 c f b SEG3 c f b SEG3 c f b
g g g g
SEG4 d GRID1 SEG4 d GRID2 SEG4 d GRID3 SEG4 d GRID4
SEG9 ee c SEG9 ee c SEG9 ee c SEG9 ee c
d d d d
SEG10 f SEG10 f SEG10 f SEG10 f
dp dp dp dp
SEG11 g SEG11 g SEG11 g SEG11 g
SEG12 dp SEG12 SEG12 dp SEG12 dp
dp

VCC

VCC
GRID4 GRID4 GRID5
GRID5
GRID3 GRID3 GRID6
R1 R2 R3
GRID6 104
GND GND 100uF
GRID2 GRID2 GRID7
MCU Interface

10K 10K 10K GRID7 GND

GND GRID1 GRID1 GRID8 GRID8
DIO DIO TM1639 SEG12 SEG12
1 GND
CLK CLK SEG11 SEG11
2
STB STB SEG10 SEG10
3
K0 SEG9 SEG9
VCC SEG4
100P 100P 100P K1 SGE4/KS4
VDD SEG3/KS3 SEG3
SEG1 SEG1/KS1 SEG2
SEG2/KS2
GND

SEG1

SEG2

SEG3

SEG4

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 Special circuit for LED drive control TM1639
Hardware circuit diagram for TM1639 to drive a common anode LED screen
GRID1 a GRID1 a GRID1 a GRID1 a
a GRID2 a GRID2 a GRID2 a
GRID2 b b b b
GRID3 c f b GRID3 c f b GRID3 c f b GRID3 c f b
g SEG1 g SEG2 g SEG3 g
GRID4 d GRID4 d GRID4 d GRID4 d SEG4
GRID5 ee c GRID5 ee c GRID5 ee c GRID5 ee c
d GRID6 d GRID6 d GRID6 d
GRID6 f f f f
dp dp dp dp
GRID7 g GRID7 g GRID7 g GRID7 g
GRID8 GRID8 dp GRID8 dp GRID8 dp
dp

GRID1 a GRID1 a GRID1 a GRID1 a

GRID2 a a a a
b GRID2 b GRID2 b GRID2 b
GRID3 c f b GRID3 c f b GRID3 c f b GRID3 c f b
g g g g
GRID4 d SEG12 GRID4 d SEG11 GRID4 d SEG10 GRID4 d SEG9
GRID5 ee c GRID5 e e c GRID5 e e c GRID5 e e c
GRID6 d d d d
f GRID6 f GRID6 f GRID6 f
GRID7 dp dp
g GRID7 g dp GRID7 g GRID7 g dp

GRID8 dp GRID8 dp GRID8 dp GRID8 dp

VCC

VCC
GRID4 GRID4 GRID5
GRID5
GRID3 GRID3 GRID6
R1 R2 R3
GRID6 104
GND GND 100uF
GRID2 GRID2
MCU Interface

10K 10K 10K GRID7 GRID7

GRID1 GRID1 GRID8 GND
GND GRID8
DIO DIO TM1639 SEG12 SEG12
1 GND
CLK CLK SEG11 SEG11
2
STB STB SEG10 SEG10
3
K0 SEG9 SEG9
VCC SEG4
100P 100P 100P K1 SGE4/KS4
VDD SEG3/KS3 SEG3
SEG1 SEG1/KS1 SEG2
SEG2/KS2
GND

SEG1

SEG2

SEG3

SEG4

▲Note： 1、During PCB board wiring, the filter capacitor between VDD and GND shall be placed as close as
possible to TM1639 to strengthen the filtering effect.
2、The three 100pF capacitors connected to the three communication ports, DIO, CLK, and STB will
reduce interference with the communication ports.
3、Considering the turn-on voltage drop of blue digital led display is about 3V, the power supply for
TM1639 should be 5V.

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 Special circuit for LED drive control TM1639
十二、Electrical Parameters：

Limit parameter (Ta = 25 ℃, Vss = 0 V)

Parameter Symbol Range Unit

Logic Supply Voltage VDD -0.5～+7.0 V

Logic input voltage VI1 -0.5 ～ VDD + 0.5 V

LED Seg drives output current IO1 -50 mA

LED Grid drives output current IO2 +200 mA

Power loss PD 400 mW

Operating temperature Topt -40 ～ +80 ℃

Storage temperature Tstg -65～+150 ℃

Normal operating range (Ta = -20 ~ + 70 ℃, Vss = 0 V)

Test
Parameter Symbol Minimum Typical Maximum Unit
Conditions
Logic Supply Voltage VDD 5 V -

High-level input voltage VIH 0.7 VDD - VDD V -

Low-level input voltage VIL 0 - 0.3 VDD V -

Electrical Characteristics (Ta = -20 ~ + 70 ℃, VDD = 4.5 ~ 5.5 V, Vss = 0 V

Parameter Symbol Minimum Typical Maximum Unit Test Conditions

SGE1～SEG12
Ioh1 20 25 40 mA
Vo = VDD-2V
SEG drives current
draw
SGE1～SEG12
Ioh2 20 30 50 mA
Vo = VDD-3V

GRID drives sink GRID1-GRID8

IOL1 80 140 - mA
current Vo=0.3V

Output pull-down
RL 10 KΩ K0～K1
resistance
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 Special circuit for LED drive control TM1639
Input current II - - ±1 μA VI = VDD / VSS
High-level input
VIH 0.7 VDD - V CLK，DIO，STB
voltage
Low-level input
VIL - - 0.3 VDD V CLK，DIO，STB
voltage
Lagging voltage VH - 0.35 - V CLK，DIO，STB
Dynamic current
IDDdyn - - 5 mA No load, Display Off
loss

Switching Characteristics (Ta = -20～ + 70 ℃, VDD = 4.5 ～5.5 V)

Parameter Symbol Minimum Typical Maximum Unit Test Conditions
Oscillation
fosc - 500 - KHz R = 16.5 KΩ
frequency
tPLZ - - 300 ns CLK → DIO
Transmission
delay
tPZL - - 100 ns CL = 15pF, RL = 10K Ω

CL =
TTZH
Rise Time - - 2 μs 300p SEG1～SEG12
1
F

CL = 300pF，SEGN，
Fall Time TTHZ - - 120 μs
GRIDN
Maximum clock
Fmax - - 1 MHz ratio=50%
frequency
Input capacitance CI - - 15 pF -

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 Special circuit for LED drive control TM1639
Timing Characteristics (Ta = -20 ~ + 70 ℃, VDD = 4.5 ~ 5.5 V)
Parameter Symbol Minimum Typical Maximum Unit Test Conditions
Clock pulse
PWCLK 400 - - ns -
width
Strobing pulse
PWSTB 1 - - μs -
width
Data setup time tSETUP 100 - - ns -
Data Hold
tHOLD 100 - - ns -
Time
CLK → STB tCLK
1 - - μs CLK↑→STB↑
time STB

Waiting time tWAIT 1 - - μs CLK↑→CLK↓

Timing Waveforms：

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 Special circuit for LED drive control TM1639
十三、 Package size for SOP24:

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 Special circuit for LED drive control TM1639
Package size for SDIP24:

All specifications and applications shown above are subject to change without prior notice.

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