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9201 East Dry Creek Road
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Los Angeles, CO 80112
CA 90074-0970

This coversheet was created by Verical, a division of Arrow Electronics, Inc. (“Verical”). The attached document was created by the part supplier,
not Verical, and is provided strictly 'as is.' Verical, its subsidiaries, affiliates, employees, and agents make no representations or warranties
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 Si5351A/B/C-B
I 2 C - P R O GRA MM A B LE A NY - F R E Q U E N C Y CMOS C L O C K
G ENERATOR + VCXO
Features
 www.silabs.com/custom-timing  Glitchless frequency changes 10-MSOP
 Generates up to 8 non-integer-related  Separate voltage supply pins:
frequencies from 8 kHz to 160 MHz Core VDD: 2.5 or 3.3 V

 I2C user definable configuration Output VDDO: 1.8, 2.5, or 3.3 V

 Exact frequency synthesis at each output  Excellent PSRR eliminates external

(0 ppm error) power supply filtering
 Highly linear VCXO  Very low power consumption
 Optional clock input (CLKIN)  Adjustable output delay
20-QFN
 Low output period jitter: < 70 ps pp, typ  Available in 2 packages types:
 Configurable spread spectrum selectable  10-MSOP: 3 outputs
at each output  20-QFN (4x4 mm): 8 outputs
 Operates from a low-cost, fixed frequency  PCIE Gen 1 compatible
crystal: 25 or 27 MHz  Supports HCSL compatible swing
 Supports static phase offset
 Programmable rise/fall time control Ordering Information:
See page 28
Applications
 HDTV, DVD/Blu-ray, set-top box  Residential gateways
 Audio/video equipment, gaming  Networking/communication
 Printers, scanners, projectors  Servers, storage
 XO replacement

Description
The Si5351 is an I2C configurable clock generator that is ideally suited for replacing
crystals, crystal oscillators, VCXOs, phase-locked loops (PLLs), and fanout buffers in
cost-sensitive applications. Based on a PLL/VCXO + high resolution MultiSynth fractional
divider architecture, the Si5351 can generate any frequency up to 160 MHz on each of its
outputs with 0 ppm error. Three versions of the Si5351 are available to meet a wide
variety of applications. The Si5351A generates up to 8 free-running clocks using an
internal oscillator for replacing crystals and crystal oscillators. The Si5351B adds an
internal VCXO and provides the flexibility to replace both free-running clocks and
synchronous clocks. It eliminates the need for higher cost, custom pullable crystals while
providing reliable operation over a wide tuning range. The Si5351C offers the same
flexibility but synchronizes to an external reference clock (CLKIN).

Functional Block Diagram

XA
Multi XA Multi Multi
XA PLLA Synth Synth Synth
0 0 OSC 0
OSC PLL PLLA
Multi Multi Multi
OSC Synth
Synth Synth
1 XB 1 XB 1
XB PLLB Multi Multi
Synth Synth
VC VCXO 2 PLLB 2
CLKIN
Multi Multi
Multi Synth
I2C Synth 3
Synth
3
N
Multi Multi
SSEN Synth Synth
OEB 4
Si5351A Multi
4
Multi
Synth Synth
N = 2 or 7 5 5
Multi Multi
Synth Synth
6 6
I2C Multi I2C Multi
Synth Synth
7 7
SSEN INTR
OEB OEB
Si5351B Si5351C

Rev. 0.75 10/12 Copyright © 2012 by Silicon Laboratories Si5351A/B/C-B

This information applies to a product under development. Its characteristics and specifications are subject to change without notice.
Si5351A/B/C-B

2 Rev. 0.75
 Si5351A/B/C-B
TABLE O F C ONTENTS

Section Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Detailed Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
3. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.1. Input Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.2. Synthesis Stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.3. Output Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.4. Spread Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.5. Control Pins (OEB, SSEN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4. I2C Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5. Configuring the Si5351 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.1. Writing a Custom Configuration to RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2. Si5351 Application Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.3. Replacing Crystals and Crystal Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.4. Replacing Crystals, Crystal Oscillators, and VCXOs . . . . . . . . . . . . . . . . . . . . . . . .19
5.5. Replacing Crystals, Crystal Oscillators, and PLLs . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.6. Applying a Reference Clock at XTAL Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.7. HCSL Compatible Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6. Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
6.1. Power Supply Decoupling/Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.2. Power Supply Sequencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.3. External Crystal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
6.4. External Crystal Load Capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.5. Unused Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
6.6. Trace Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7. Register Map Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
8. Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
9. Si5351 Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
9.1. Si5351A 20-pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
9.2. Si5351B 20-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
9.3. Si5351C 20-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
9.4. Si5351A 10-Pin MSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
10. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
11. Package Outlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
11.1. 20-pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
11.2. 10-Pin MSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Rev. 0.75 3
Si5351A/B/C-B
1. Electrical Specifications

Table 1. Recommended Operating Conditions

Parameter Symbol Test Condition Min Typ Max Unit

Ambient Temperature TA –40 25 85 °C

3.0 3.3 3.60 V

Core Supply Voltage VDD
2.25 2.5 2.75 V

1.71 1.8 1.89 V

Output Buffer Voltage VDDOx 2.25 2.5 2.75 V

3.0 3.3 3.60 V

Notes:All minimum and maximum specifications are guaranteed and apply across the recommended operating conditions.
Typical values apply at nominal supply voltages and an operating temperature of 25 °C unless otherwise noted.
VDD and VDDOx can be operated at independent voltages.
Power supply sequencing for VDD and VDDOx requires that all VDDOx be powered up either before or at the same
time as VDD.

Table 2. DC Characteristics
(VDD = 2.5 V ±10%, or 3.3 V ±10%, TA = –40 to 85 °C)

Parameter Symbol Test Condition Min Typ Max Unit

Enabled 3 outputs — 22 35 mA
Core Supply Current IDD
Enabled 8 outputs — 27 45 mA
Output Buffer Supply Current
IDDOx CL = 5 pF — 2.2 5 mA
(Per Output)*
CLKIN, SDA, SCL
ICLKIN — — 10 µA
Input Current Vin < 3.6 V
IVC VC — — 30 µA
3.3 V VDDO, default high
Output Impedance ZO — 50 — 
drive
*Note: Output clocks less than or equal to 100 MHz.

4 Rev. 0.75
 Si5351A/B/C-B

Table 3. AC Characteristics
(VDD = 2.5 V ±10%, or 3.3 V ±10%, TA = –40 to 85 °C)

Parameter Symbol Test Condition Min Typ Max Unit

From VDD = VDDmin to valid
Power-up Time TRDY output clock, CL = 5 pF, — 1 10 ms
fCLKn > 1 MHz
From OEB pulled low to valid
Output Enable Time TOE clock output, CL = 5 pF, — — 10 µs
fCLKn > 1 MHz
Output Phase Offset PSTEP — 333 — ps/step
Spread Spectrum Frequency Down spread –0.1 — –2.5 %
SSDEV
Deviation Center spread ±0.1 — ±1.5 %
Spread Spectrum Modulation
SSMOD 30 31.5 33 kHz
Rate
VCXO Specifications (Si5351B only)
VCXO Control Voltage Range Vc 0 VDD/2 VDD V
VCXO Gain (configurable) Kv Vc = 10–90% of VDD, VDD = 3.3 V 18 — 150 ppm/V
VCXO Control Voltage Linearity KVL Vc = 10–90% of VDD –5 — +5 %
VCXO Pull Range
PR VDD = 3.3 V* ±30 0 ±240 ppm
(configurable)
VCXO Modulation Bandwidth — 10 — kHz
*Note: Contact Silicon Labs for 2.5 V VCXO operation.

Table 4. Input Clock Characteristics

(VDD = 2.5 V ±10%, or 3.3 V ±10%, TA = –40 to 85 °C)

Parameter Symbol Test Condition Min Typ Max Unit

CLKIN Input Low Voltage VIL –0.1 — 0.3 x VDD V

CLKIN Input High Voltage VIH 0.7 x VDD — 3.60 V

CLKIN Frequency Range fCLKIN 10 — 100 MHz

Rev. 0.75 5
Si5351A/B/C-B

Table 5. Output Clock Characteristics

(VDD = 2.5 V ±10%, or 3.3 V ±10%, TA = –40 to 85 °C)

Parameter Symbol Test Condition Min Typ Max Unit

Frequency Range FCLK 0.008 — 160 MHz

Load Capacitance CL — — 15 pF

Measured at VDD/2,
Duty Cycle DC 45 50 55 %
fCLK = 50 MHz

tr 20%–80%, CL = 5 pF, — 1 1.5 ns

Rise/Fall Time
tf Default high drive strength — 1 1.5 ns

Output High Voltage VOH VDD – 0.6 — — V

CL = 5 pF
Output Low Voltage VOL — — 0.6 V

20-QFN, 4 outputs running, ps, pk-

— 40 95
1 per VDDO pk
Period Jitter* JPER
10-MSOP or 20-QFN, ps, pk-
— 70 140
all outputs running pk

20-QFN, 4 outputs running,

— 50 90 ps, pk
1 per VDDO
Cycle-to-Cycle Jitter* JCC
10-MSOP or 20-QFN,
— 70 130 ps, pk
all outputs running

20-QFN, 4 outputs running, ps, pk-

— 50 95
1 per VDDO pk
Period Jitter VCXO* JPER_VCXO
10-MSOP or 20-QFN, ps, pk-
— 70 150
all outputs running pk

20-QFN, 4 outputs running,

— 50 90 ps, pk
Cycle-to-Cycle Jitter 1 per VDDO
JCC_VCXO
VCXO* 10-MSOP or 20-QFN,
— 70 140 ps, pk
all outputs running

*Note: Measured over 10k cycles. Jitter is highly dependent on device frequency configuration. Specifications represent a
"worst case, real world" frequency plan; actual performance may be substantially better. For 3 output 10-MSOP
package, measured with clock outputs of 74.25, 24.576, 48 MHz. For 8 output 20-QFN package, measured with clock
outputs of 33.33, 74.25, 27, 24.576, 22.5792, 28.322, 125, 48 MHz.

6 Rev. 0.75
 Si5351A/B/C-B

Table 6. Crystal Requirements1,2

Parameter Symbol Min Typ Max Unit

Crystal Frequency fXTAL 25 — 27 MHz

Load Capacitance CL 6 — 12 pF

Equivalent Series Resistance rESR — — 150 

Crystal Max Drive Level dL — — 100 µW

Notes:
1. Crystals which require load capacitances of 6, 8, or 10 pF should use the device’s internal load capacitance for
optimum performance. See register 183 bits 7:6. A crystal with a 12 pF load capacitance requirement should use a
combination of the internal 10 pF load capacitors in addition to external 2 pF load capacitors.
2. Refer to “AN551: Crystal Selection Guide” for more details.

Table 7. I2C Specifications (SCL,SDA)1

Parameter Symbol Test Condition Standard Mode Fast Mode Unit

100 kbps 400 kbps
Min Max Min Max
LOW Level 0.3 x VDDI2
VILI2C –0.5 –0.5 0.3 x VDDI2C2 V
Input Voltage C

HIGH Level 0.7 x VDDI2

VIHI2C 3.6 0.7 x VDDI2C2 3.6 V
Input Voltage C

Hysteresis of
Schmitt Trigger VHYS — — 0.1 — V
Inputs
LOW Level
Output Voltage
(open drain or
VOLI2C2 VDDI2C2 = 2.5/3.3 V 0 0.4 0 0.4 V
open collector)
at 3 mA Sink
Current
Input Current III2C –10 10 –10 10 µA
Capacitance for
CII2C VIN = –0.1 to VDDI2C — 4 — 4 pF
Each I/O Pin
I2C Bus
TTO Timeout Enabled 25 35 25 35 ms
Timeout
Notes:
1. Refer to NXP’s UM10204 I2C-bus specification and user manual, revision 03, for further details, go to:
www.nxp.com/acrobat_download/usermanuals/UM10204_3.pdf.
2. Only I2C pullup voltages (VDDI2C) of 2.25 to 3.63 V are supported.

Rev. 0.75 7
Si5351A/B/C-B
Table 8. Thermal Characteristics

Parameter Symbol Test Condition Package Value Unit

Thermal Resistance 10-MSOP 131 °C/W

JA Still Air
Junction to Ambient 20-QFN 51 °C/W

Thermal Resistance 10-MSOP 43 °C/W

JC Still Air
Junction to Case 20-QFN 16 °C/W

Table 9. Absolute Maximum Ratings1

Parameter Symbol Test Condition Value Unit

DC Supply Voltage VDD_max –0.5 to 3.8 V

VIN_CLKIN CLKIN, SCL, SDA –0.5 to 3.8 V

Input Voltage VIN_VC VC –0.5 to (VDD+0.3) V

VIN_XA/B Pins XA, XB –0.5 to 1.3 V V

Junction Temperature TJ –55 to 150 °C

Soldering Temperature (Pb-free

TPEAK 260 °C
profile)2

Soldering Temperature Time at

TP 20–40 Sec
TPEAK (Pb-free profile)2

Notes:
1. Permanent device damage may occur if the absolute maximum ratings are exceeded. Functional operation should be
restricted to the conditions as specified in the operational sections of this data sheet. Exposure to absolute maximum
rating conditions for extended periods may affect device reliability.
2. The device is compliant with JEDEC J-STD-020.

8 Rev. 0.75
 Si5351A/B/C-B
2. Detailed Block Diagrams

VDD VDDO
Si5351A 3-Output

PLL MultiSynth
A R0 CLK0
XA 0
OSC
XB PLL MultiSynth
B R1 CLK1
1

SDA I2C MultiSynth

Interface R2 CLK2
SCL 2

GND 10-MSOP

VDD
Si5351A 8-Output
VDDOA
MultiSynth
PLL R0
0 CLK0
A
XA MultiSynth CLK1
R1
OSC 1
XB PLL VDDOB
MultiSynth
B R2
2 CLK2
MultiSynth CLK3
R3
3
A0 VDDOC
MultiSynth
I2C R4
SDA 4 CLK4
Interface
MultiSynth CLK5
SCL R5
5
VDDOD
MultiSynth
OEB R6
Control 6 CLK6
Logic MultiSynth CLK7
SSEN R7
7

GND 20-QFN

Figure 1. Block Diagrams of 3-Output and 8-Output Si5351A Devices

Rev. 0.75 9
Si5351A/B/C-B

VDD
Si5351B
VDDOA
MultiSynth
XA R0
0 CLK0
OSC PLL
MultiSynth CLK1
XB R1
1
VDDOB
VCXO MultiSynth
R2
2 CLK2
VC
MultiSynth CLK3
R3
3
VDDOC
MultiSynth
R4
SDA 4 CLK4
I2C
SCL Interface MultiSynth CLK5
R5
5
VDDOD
MultiSynth
OEB R6
Control 6 CLK6
Logic
SSEN MultiSynth CLK7
R7
7

GND 20-QFN

VDD
Si5351C
VDDOA
MultiSynth
XA R0
0 CLK0
OSC PLL
A MultiSynth CLK1
XB R1
1
VDDOB
MultiSynth
PLL R2
2 CLK2
CLKIN B
MultiSynth CLK3
R3
3
VDDOC
MultiSynth
SDA R4
4 CLK4
I2C
SCL MultiSynth CLK5
Interface R5
5
INTR VDDOD
MultiSynth
R6
6 CLK6
OEB Control
Logic MultiSynth CLK7
R7
7

GND 20-QFN

Figure 2. Block Diagrams of Si5351B and Si5351C 8-Output Devices

10 Rev. 0.75
 Si5351A/B/C-B
3. Functional Description
The Si5351 is a versatile I2C programmable clock generator that is ideally suited for replacing crystals, crystal
oscillators, VCXOs, PLLs, and buffers. A block diagram showing the general architecture of the Si5351 is shown in
Figure 3. The device consists of an input stage, two synthesis stages, and an output stage.
The input stage accepts an external crystal (XTAL), a control voltage input (VC), or a clock input (CLKIN)
depending on the version of the device (A/B/C). The first stage of synthesis multiplies the input frequencies to an
high-frequency intermediate clock, while the second stage of synthesis uses high resolution MultiSynth fractional
dividers to generate the desired output frequencies. Additional integer division is provided at the output stage for
generating output frequencies as low as 8 kHz. Crosspoint switches at each of the synthesis stages allows total
flexibility in routing any of the inputs to any of the outputs.
Because of this high resolution and flexible synthesis architecture, the Si5351 is capable of generating
synchronous or free-running non-integer related clock frequencies at each of its outputs, enabling one device to
synthesize clocks for multiple clock domains in a design.

Input Synthesis Synthesis Output

Stage Stage 1 Stage 2 Stage

Multi VDDOA
Synth R0
0 CLK0
Multi CLK1
Synth R1
CLKIN Div 1
PLL A
Multi VDDOB
(SSC)
Synth R2
XA 2 CLK2
PLL B Multi CLK3
(VCXO) Synth R3
XTAL OSC 3
Multi VDDOC
XB Synth R4
4 CLK4
Multi CLK5
Synth R5
5
VC VCXO Multi VDDOD
Synth R6
6 CLK6
Multi CLK7
Synth R7
7

Figure 3. Si5351 Block Diagram

Rev. 0.75 11
Si5351A/B/C-B
3.1. Input Stage
3.1.1. Crystal Inputs (XA, XB)
The Si5351 uses a fixed-frequency standard AT-cut crystal as a reference to the internal oscillator. The output of
the oscillator can be used to provide a free-running reference to one or both of the PLLs for generating
asynchronous clocks. The output frequency of the oscillator will operate at the crystal frequency, either 25 MHz or
27 MHz. The crystal is also used as a reference to the VCXO to help maintain its frequency accuracy.
Internal load capacitors (CL) are provided to eliminate the need for external components when connecting a crystal
to the Si5351. Options for internal load capacitors are 6, 8, or 10 pF. Crystals with alternate load capacitance
requirements are supported using additional external load capacitors as shown in Figure 4. Refer to application
note AN551 for crystal recommendations.

CL XA

XB
CL
Optional CL CL Selectable internal
Additional external load capacitors
load capacitors 6 pF, 8 pF, 10 pF
(< 2 pF)

Figure 4. External XTAL with Optional Load Capacitors

3.1.2. External Clock Input (CLKIN)
The external clock input is used as a clock reference for the PLLs when generating synchronous clock outputs.
CLKIN can accept any frequency from 10 to 100 MHz. A divider at the input stage limits the PLL input frequency to
30 MHz.
3.1.3. Voltage Control Input (VC)
The VCXO architecture of the Si5350B eliminates the need for an external pullable crystal. Only a standard, low-
cost, fixed-frequency (25 or 27 MHz) AT-cut crystal is required.
The tuning range of the VCXO is configurable allowing for a wide variety of applications. Key advantages of the
VCXO design in the Si5351 include high linearity, a wide operating range (linear from 10 to 90% of VDD), and
reliable startup and operation. Refer to Table 3 on page 5 for VCXO specification details.
A unique feature of the Si5351B is its ability to generate multiple output frequencies controlled by the same control
voltage applied to the VC pin. This replaces multiple PLLs or VCXOs that would normally be locked to the same
reference. An example is illustrated in Figure 5 on page 13.

12 Rev. 0.75
 Si5351A/B/C-B
3.2. Synthesis Stages
The Si5351 uses two stages of synthesis to generate its final output clocks. The first stage uses PLLs to multiply
the lower frequency input references to a high-frequency intermediate clock. The second stage uses high-
resolution MultiSynth fractional dividers to generate frequencies in the range of 1 MHz to 112.5 MHz. It is also
possible to generate two unique frequencies up to 160 MHz on two or more of the outputs.
A crosspoint switch at the input of the first stage allows each of the PLLs to lock to the CLKIN or the XTAL input.
This allows each of the PLLs to lock to a different source for generating independent free-running and synchronous
clocks. Alternatively, both PLLs could lock to the same source. The crosspoint switch at the input of the second
stage allows any of the MultiSynth dividers to connect to PLLA or PLLB. This flexible synthesis architecture allows
any of the outputs to generate synchronous or non-synchronous clocks, with spread spectrum or without spread
spectrum, and with the flexibility of generating non-integer related clock frequencies at each output.
All VCXO outputs are generated by PLLB only. The Multisynth high-resolution dividers can synthesize VCXO
outputs with center frequencies up to 112.5 MHz. The center frequency is then controlled (or pulled) by the VC
input. An interesting feature of the Si5351 is that the VCXO output can be routed to more than one MultiSynth
divider. This creates a VCXO with multiple output frequencies controlled from one VC input as shown in Figure 5.
Frequencies down to 8 kHz can be generated by applying the R divider at the output of the Multisynth (see
Figure 5 below).

Fixed Frequency
XA XB
Crystal (non-pullable)

Multi The clock frequency

OSC Synth R0 CLK0
0 generated from CLK0 is
controlled by the VC input

Control VC Multi
VCXO Synth R1 CLK1
Voltage 1

Additional MultiSynths
Multi can be “linked” to the
Synth R2 CLK2
2 VCXO to generate
additional clock
frequencies

Figure 5. Using the Si5351 as a Multi-Output VCXO

Rev. 0.75 13
Si5351A/B/C-B
3.3. Output Stage
An additional level of division (R) is available at the output stage for generating clocks as low as 8 kHz. All output
drivers generate CMOS level outputs with separate output voltage supply pins (VDDOx) allowing a different voltage
signal level (1.8, 2.5, or 3.3 V) at each of the four 2-output banks.
3.4. Spread Spectrum
Spread spectrum can be enabled on any of the clock outputs that use PLLA as its reference. Spread spectrum is
useful for reducing electromagnetic interference (EMI). Enabling spread spectrum on an output clock modulates its
frequency, which effectively reduces the overall amplitude of its radiated energy. Note that spread spectrum is not
available on clocks synchronized to PLLB or to the VCXO.
The Si5351 supports several levels of spread spectrum allowing the designer to chose an ideal compromise
between system performance and EMI compliance.

Reduced Reduced
Center
Amplitude Amplitude
Frequency
and EMI and EMI
Amplitude

fc fc fc
No Spread
Center Spread Down Spread
Spectrum

Figure 6. Available Spread Spectrum Profiles

3.5. Control Pins (OEB, SSEN)

The Si5351 offers control pins for enabling/disabling clock outputs and spread spectrum.
3.5.1. Output Enable (OEB)
The output enable pin allows enabling or disabling outputs clocks. Output clocks are enabled when the OEB pin is
held low, and disabled when pulled high. When disabled, the output state is configurable as output high, output low,
or high-impedance.
The output enable control circuitry ensures glitchless operation by starting the output clock cycle on the first leading
edge after OEB is pulled low. When OEB is pulled high, the clock is allowed to complete its full clock cycle before
going into a disabled state.

3.5.2. Spread Spectrum Enable (SSEN)—Si5351A and Si5351B only

This control pin allows disabling the spread spectrum feature for all outputs that were configured with spread
spectrum enabled. Hold SSEN low to disable spread spectrum. The SSEN pin provides a convenient method of
evaluating the effect of using spread spectrum clocks during EMI compliance testing.

14 Rev. 0.75
 Si5351A/B/C-B

4. I2C Interface
Many of the functions and features of the Si5351 are controlled by reading and writing to the RAM space using the
I2C interface. The following is a list of the common features that are controllable through the I2C interface.
Read Status Indicators
Crystal
Reference Loss of signal, LOS_XTAL, reg0[3]
CLKIN Loss of signal, LOS_CLKIN, reg0[4]
PLLA and/or PLLB Loss of lock, LOL_A or LOL_B, reg0[6:5]

Configuration of multiplication and divider values for the PLLs, MultiSynth dividers
Configuration of the Spread Spectrum profile (down or center spread, modulation percentage)
Control of the cross point switch selection for each of the PLLs and MultiSynth dividers
Set output clock options
Enable/disable for each clock output
Invert/non-invert for each clock output
Output divider values (2n, n=1.. 7)
Output state when disabled (stop hi, stop low, Hi-Z)

Output phase offset

The I2C interface operates in slave mode with 7-bit addressing and can operate in Standard-Mode (100 kbps) or
Fast-Mode (400 kbps) and supports burst data transfer with auto address increments.
The I2C bus consists of a bidirectional serial data line (SDA) and a serial clock input (SCL) as shown in Figure 7.
Both the SDA and SCL pins must be connected to the VDD supply via an external pull-up as recommended by the
I2C specification.

VDD

>1k >1k
Si5351
SCL
I2C Bus
SDA

4.7 k
INTR

I2C Address Select: A0

Pull-up to VDD (A0 = 1)
Pull-down to GND (A0 = 0)

Figure 7. I2C and Control Signals

The 7-bit device (slave) address of the Si5351 consist of a 6-bit fixed address plus a user selectable LSB bit as
shown in Figure 8. The LSB bit is selectable as 0 or 1 using the optional A0 pin which is useful for applications that
require more than one Si5351 on a single I2C bus.

6 5 4 3 2 1 0

Slave Address 1 1 0 0 0 0 0/1

A0

Figure 8. Si5351 I2C Slave Address

Data is transferred MSB first in 8-bit words as specified by the I2C specification. A write command consists of a 7-
bit device (slave) address + a write bit, an 8-bit register address, and 8 bits of data as shown in Figure 9. A write
burst operation is also shown where every additional data word is written using to an auto-incremented address.

Rev. 0.75 15
Si5351A/B/C-B

Write Operation – Single Byte

S Slv Addr [6:0] 0 A Reg Addr [7:0] A Data [7:0] A P

Write Operation - Burst (Auto Address Increment)

S Slv Addr [6:0] 0 A Reg Addr [7:0] A Data [7:0] A Data [7:0] A P

Reg Addr +1

From slave to master 1 – Read

0 – Write
From master to slave A – Acknowledge (SDA LOW)
N – Not Acknowledge (SDA HIGH)
S – START condition
P – STOP condition

Figure 9. I2C Write Operation

A read operation is performed in two stages. A data write is used to set the register address, then a data read is
performed to retrieve the data from the set address. A read burst operation is also supported. This is shown in
Figure 10.

Read Operation – Single Byte

S Slv Addr [6:0] 0 A Reg Addr [7:0] A P

S Slv Addr [6:0] 1 A Data [7:0] N P

Read Operation - Burst (Auto Address Increment)

S Slv Addr [6:0] 0 A Reg Addr [7:0] A P

S Slv Addr [6:0] 1 A Data [7:0] A Data [7:0] N P

Reg Addr +1

From slave to master 1 – Read

0 – Write
From master to slave A – Acknowledge (SDA LOW)
N – Not Acknowledge (SDA HIGH)
S – START condition
P – STOP condition

Figure 10. I2C Read Operation

AC and DC electrical specifications for the SCL and SDA pins are shown in Table 7. The timing specifications and
timing diagram for the I2C bus is compatible with the I2C-Bus Standard. SDA timeout is supported for compatibility
with SMBus interfaces.

16 Rev. 0.75
 Si5351A/B/C-B
5. Configuring the Si5351
The Si5351 is a highly flexible clock generator which is entirely configurable through its I2C interface. The device’s
default configuration is stored in non-volatile memory (NVM) as shown in Figure 11. The NVM is a one time
programmable memory (OTP) which can store a custom user configuration at power-up. This is a useful feature for
applications that need a clock present at power-up (e.g., for providing a clock to a processor).

Power-Up

NVM
(OTP)
RAM
Default
Config

I2C
Figure 11. Si5351 Memory Configuration
During a power cycle the contents of the NVM are copied into random access memory (RAM), which sets the
device configuration that will be used during normal operation. Any changes to the device configuration after
power-up are made by reading and writing to registers in the RAM space through the I2C interface.
5.1. Writing a Custom Configuration to RAM
To simplify device configuration, Silicon Labs has released the ClockBuilder Desktop. The software serves two
purposes: to configure the Si5351 with optimal configuration based on the desired frequencies and to control the
EVB when connected to a host PC.
The optimal configuration can be saved from the software in text files that can be used in any system, which
configures the device over I2C. ClockBuilder Desktop can be downloaded from www.silabs.com/ClockBuilder and
runs on Windows XP, Windows Vista, and Windows 7.
Once the configuration file has been saved, the device can be programmed via I2C by following the steps shown in
Figure 12.

Rev. 0.75 17
Si5351A/B/C-B

Disable Outputs
Set CLKx_DIS high; Reg. 3 = 0xFF

Powerdown all output drivers

Reg. 16, 17, 18, 19, 20, 21, 22, 23 =
0x80

Set interrupt masks

(see register 2 description)

Register Write new configuration to device using

Map the contents of the register map
generated by ClockBuilder Desktop. This
step also powers up the output drivers.
Use ClockBuilder 149-170
(Registers 15-92 ,and and 183)
149-170)
Desktop v3.1 or later

Apply PLLA and PLLB soft reset

Reg. 177 = 0xAC

Enable desired outputs

(see Register 3)

Figure 12. I2C Programming Procedure

18 Rev. 0.75
 Si5351A/B/C-B
5.2. Si5351 Application Examples
The Si5351 is a versatile clock generator which serves a wide variety of applications. The following examples show
how it can be used to replace crystals, crystal oscillators, VCXOs, and PLLs.
5.3. Replacing Crystals and Crystal Oscillators
Using an inexpensive external crystal, the Si5351A can generate up to 8 different free-running clock frequencies
for replacing crystals and crystal oscillators. A 3-output version packaged in a small 10-MSOP is also available for
applications that require fewer clocks. An example is shown in Figure 13.

XA Multi CLK0 125 MHz Ethernet

Synth PHY
0
27 MHz OSC PLL
Multi CLK1 48 MHz
XB USB
Synth Controller
1
Multi CLK2 28.322 MHz HDMI
Synth
2 Port

Multi CLK3 74.25 MHz

Synth
3
Multi CLK4 74.25/1.001 MHz
Synth
4 Video/Audio
Multi CLK5 24.576 MHz Processor
Synth
5
Multi CLK6 22.5792 MHz
Synth
6
Multi CLK7 33.3333 MHz
Synth CPU
Si5351A 7

Note: Si5351A replaces crystals, XOs, and PLLs.

Figure 13. Using the Si5351A to Replace Multiple Crystals, Crystal Oscillators, and PLLs
5.4. Replacing Crystals, Crystal Oscillators, and VCXOs
The Si5351B combines free-running clock generation and a VCXO in a single package for cost sensitive video
applications. An example is shown in Figure 14.

Free-running
Clocks
XA CLK0 Ethernet
Multi 125 MHz PHY
Synth
0
27 MHz OSC PLL
Multi CLK1 48 MHz
XB USB
Synth
1 Controller

Multi CLK2 28.322 MHz

Synth
2 HDMI
Port

Multi CLK3 74.25 MHz

VC Synth
3
VCXO
Multi CLK4 74.25/1.001 MHz Video/Audio
Synth
4 Processor

Multi CLK5 24.576 MHz

Synth
5
Si5351B VCXO Clock
Outputs

Note: FBW = 10 kHz

Figure 14. Using the Si5351B to Replace Crystals, Crystal Oscillators, VCXOs, and PLLs

Rev. 0.75 19
Si5351A/B/C-B
5.5. Replacing Crystals, Crystal Oscillators, and PLLs
The Si5350C generates synchronous clocks for applications that require a fully integrated PLL instead of a VCXO.
Because of its dual PLL architecture, the Si5351C is capable of generating both synchronous and free-running
clocks. An example is shown in Figure 15.

Free-running
Clocks

XA CLK0 Ethernet
Multi 125 MHz PHY
Synth
0
25 MHz OSC PLL
Multi CLK1 48 MHz
XB USB
Synth
1 Controller

Multi CLK2 28.322 MHz

Synth
2 HDMI
Port

Multi CLK3 74.25 MHz

CLKIN Synth
3
54 MHz PLL
Multi CLK4 74.25/1.001 MHz Video/Audio
Synth
4 Processor

Multi CLK5 24.576 MHz

Synth
5
Si5351C
Synchronous
Clocks

Figure 15. Using the Si5351C to Replace Crystals, Crystal Oscillators, and PLLs
5.6. Applying a Reference Clock at XTAL Input
The Si5351 can be driven with a clock signal through the XA input pin. This is especially useful when in need of
generating clock outputs in two synchronization domains. With the Si5351C, one reference clock can be provided
at the CLKIN pin and at XA.

VIN = 1 VPP
Multi
25/27 MHz Synth
XA PLLA
0
0.1 µF OSC Multi
Synth
1
XB PLLB

Multi
Note: Float the XB input while driving Synth
N
the XA input with a clock

Figure 16. Si5351 Driven by a Clock Signal

20 Rev. 0.75
 Si5351A/B/C-B
5.7. HCSL Compatible Outputs
The Si5351 can be configured to support HCSL compatible swing when the VDDO of the output pair of interest is
set to 2.5 V (i.e., VDDOA must be 2.5 V when using CLK0/1; VDDOB must be 2.5 V for CLK2/3 and so on).
The circuit in the figure below must be applied to each of the two clocks used, and one of the clocks in the pair
must also be inverted to generate a differential pair. See register setting CLKx_INV.

ZO = 50  R1
Multi
PLLA Synth
0 0 511 

OSC 240  R2 HCSL

CLKIN
PLLB ZO = 50  R1
Multi
Synth
1 0 511 
240  R2

Multi
Synth Note: The complementary -180 degree
N
out of phase output clock is generated
using the INV function

Figure 17. Si5351 Output is HCSL Compatible

Rev. 0.75 21
Si5351A/B/C-B
6. Design Considerations
The Si5351 is a self-contained clock generator that requires very few external components. The following general
guidelines are recommended to ensure optimum performance. Refer to “AN554: Si5350/51 PCB Layout Guide” for
additional layout recommendations.
6.1. Power Supply Decoupling/Filtering
The Si5351 has built-in power supply filtering circuitry and extensive internal Low Drop Out (LDO) voltage
regulators to help minimize the number of external bypass components. All that is recommended is one 0.1 to
1.0 µF decoupling capacitor per power supply pin. This capacitor should be mounted as close to the VDD and
VDDOx pins as possible without using vias.
6.2. Power Supply Sequencing
The VDD and VDDOx (i.e., VDDO0, VDDO1, VDDO2, VDDO3) power supply pins have been separated to allow
flexibility in output signal levels. If a minimum output-to-output skew is important, then all VDDOx must be applied
before VDD. Unused VDDOx pins should be tied to VDD.
6.3. External Crystal
The external crystal should be mounted as close to the pins as possible using short PCB traces. The XA and XB
traces should be kept away from other high-speed signal traces. See “AN551: Crystal Selection Guide” for more
details.
6.4. External Crystal Load Capacitors
The Si5351 provides the option of using internal and external crystal load capacitors. If internal load capacitance is
insufficient, capacitors of value < 2 pF may be used to increased equivalent load capacitance. If external load
capacitors are used, they should be placed as close to the XA/XB pads as possible. See “AN551: Crystal Selection
Guide” for more details.
6.5. Unused Pins
Unused voltage control pin should be tied to GND.
Unused CLKIN pin should be tied to GND.
Unused XA/XB pins should be left floating. Refer to "5.6. Applying a Reference Clock at XTAL Input" on page 20
when using XA as a clock input pin.
Unused output pins (CLK0–CLK7) should be left floating.
Unused VDDOx pins should be tied to VDD.
6.6. Trace Characteristics
The Si5351A/B/C features various output current drive strengths. It is recommended to configure the trace
characteristics as shown in Figure 18 when the default high drive strength is used.

ZO = 50 ohms

R = 0 ohms
CLK
(Optional resistor for
EMI management)
Length = No Restrictions

Figure 18. Recommended Trace Characteristics with Default Drive Strength Setting
Note: Jitter is only specified at default high drive strength.

22 Rev. 0.75
 Si5351A/B/C-B
7. Register Map Summary
For many applications, the Si5351's register values are easily configured using ClockBuilder Desktop software.
However, for customers interested in using the Si5351 in operating modes beyond the capabilities available with
ClockBuilder™, refer to “AN619: Manually Generating an Si5351 Register Map” for a detailed description of the
Si5351 registers and their usage.
8. Register Descriptions
Refer to “AN619: Manually Generating an Si5351 Register Map” for a detailed description of Si5351 registers.

Rev. 0.75 23
Si5351A/B/C-B
9. Si5351 Pin Descriptions
9.1. Si5351A 20-pin QFN

18 VDDOC
19 CLK4

17 CLK5

16 CLK6
20 VDD
XA 1 15 CLK7

XB 2 14 VDDOD
GND
A0 3 PAD 13 CLK0

SCL 4 12 CLK1

SDA 5 11 VDDOA

VDDOB 10
7

9
8
6
SSEN

CLK3
OEB

CLK2
Figure 19. Si5315A 20-QFN Top View

Table 10. Si5351A Pin Descriptions

Pin
Pin Name
Number Pin Type1 Function

XA 1 I Input pin for external crystal.

XB 2 I Input pin for external crystal.
CLK0 13 O Output clock 0.
CLK1 12 O Output clock 1.
CLK2 9 O Output clock 2.
CLK3 8 O Output clock 3.
CLK4 19 O Output clock 4.
CLK5 17 O Output clock 5.
CLK6 16 O Output clock 6.
CLK7 15 O Output clock 7.
A0 3 I I2C address bit.
SCL 4 I I2C bus serial clock input. Pull-up to VDD core with 1 k
SDA 5 I/O I2C bus serial data input. Pull-up to VDD core with 1 k
SSEN 6 I Spread spectrum enable. High = enabled, Low = disabled.
OEB 7 I Output driver enable. Low = enabled, High = disabled.
VDD 20 P Core voltage supply pin. See 6.2.
VDDOA 11 P Output voltage supply pin for CLK0 and CLK1. See 6.2.
VDDOB 10 P Output voltage supply pin for CLK2 and CLK3. See 6.2.
VDDOC 18 P Output voltage supply pin for CLK4 and CLK5. See 6.2.
VDDOD 14 P Output voltage supply pin for CLK6 and CLK7. See 6.2.
GND Center Pad P Ground. Use multiple vias to ensure a solid path to GND.
1. I = Input, O = Output, P = Power.
2. Input pins are not internally pulled up.

24 Rev. 0.75
 Si5351A/B/C-B
9.2. Si5351B 20-Pin QFN

18 VDDOC
19 CLK4

17 CLK5

16 CLK6
20 VDD
CLK7
XA 1 15
VDDOD
XB 2 14
GND CLK0
VC 3 PAD 13
CLK1
SCL 4 12
VDDOA
SDA 5 11

VDDOB 10
7

9
8
6

CLK3
OEB

CLK2
SSEN

Figure 20. Si5351B 20-QFN Top View*

Table 11. Si5351B Pin Descriptions

Pin
Pin Name
Number Pin Type1 Function

XA 1 I Input pin for external crystal

XB 2 I Input pin for external crystal
CLK0 13 O Output clock 0
CLK1 12 O Output clock 1
CLK2 9 O Output clock 2
CLK3 8 O Output clock 3
CLK4 19 O Output clock 4
CLK5 17 O Output clock 5
CLK6 16 O Output clock 6
CLK7 15 O Output clock 7
VC 3 I VCXO control voltage input
SCL 4 I I2C bus serial clock input. Pull-up to VDD core with 1 k
SDA 5 I/O I2C bus serial data input. Pull-up to VDD core with 1 k
SSEN 6 I Spread spectrum enable. High = enabled, Low = disabled.
OEB 7 I Output driver enable. Low = enabled, High = disabled.
VDD 20 P Core voltage supply pin
VDDOA 11 P Output voltage supply pin for CLK0 and CLK1. See 6.2
VDDOB 10 P Output voltage supply pin for CLK2 and CLK3. See 6.2
VDDOC 18 P Output voltage supply pin for CLK4 and CLK5. See 6.2
VDDOD 14 P Output voltage supply pin for CLK6 and CLK7. See 6.2
GND Center Pad P Ground
1. I = Input, O = Output, P = Power
2. Input pins are not internally pulled up.

Rev. 0.75 25
Si5351A/B/C-B
9.3. Si5351C 20-Pin QFN

18 VDDOC
19 CLK4

17 CLK5

16 CLK6
20 VDD
XA 1 15 CLK7

XB 2 14 VDDOD
GND
INTR 3 PAD 13 CLK0

SCL 4 12 CLK1

SDA 5 11 VDDOA

VDDOB 10
7

9
8
6
CLKIN

CLK3
OEB

CLK2
Table 12. Si5351C Pin Descriptions
Pin
Pin Name Number Pin Type1 Function
20-QFN
XA 1 I Input pin for external crystal.
XB 2 I Input pin for external crystal.
CLK0 13 O Output clock 0.
CLK1 12 O Output clock 1.
CLK2 9 O Output clock 2.
CLK3 8 O Output clock 3.
CLK4 19 O Output clock 4.
CLK5 17 O Output clock 5.
CLK6 16 O Output clock 6.
CLK7 15 O Output clock 7.
INTR 3 O Interrupt pin. Open drain active low output, requires a pull-up
resistor greater than 1 k
SCL 4 I I2C bus serial clock input. Pull-up to VDD core with 1 k
SDA 5 I/O I2C bus serial data input. Pull-up to VDD core with 1 k
CLKIN 6 I PLL clock input.
OEB 7 I Output driver enable. Low = enabled, High = disabled.
VDD 20 P Core voltage supply pin
VDDOA 11 P Output voltage supply pin for CLK0 and CLK1. See 6.2
VDDOB 10 P Output voltage supply pin for CLK2 and CLK3. See 6.2
VDDOC 18 P Output voltage supply pin for CLK4 and CLK5. See 6.2
VDDOD 14 P Output voltage supply pin for CLK6 and CLK7. See 6.2
GND Center Pad P Ground.
Notes:
1. I = Input, O = Output, P = Power.
2. Input pins are not internally pulled up.

26 Rev. 0.75
 Si5351A/B/C-B
9.4. Si5351A 10-Pin MSOP

VDD 1 10 CLK0

XA 2 9 CLK1

XB 3 8 GND

SCL 4 7 VDDO

SDA 5 6 CLK2

Figure 21. Si5351A 10-MSOP Top View

Table 13. Si5351A 10-MSOP Pin Descriptions

Pin
Pin Name Number Pin Type* Function
10-MSOP

XA 2 I Input pin for external crystal.

XB 3 I Input pin for external crystal.

CLK0 10 O Output clock 0.

CLK1 9 O Output clock 1.

CLK2 6 O Output clock 2.

SCL 4 I Serial clock input for the I2C bus. This pin must be pulled-up using a pull-
up resistor of at least 1 k.
SDA 5 I/O Serial data input for the I2C bus. This pin must be pulled-up using a pull-up
resistor of at least 1 k.

VDD 1 P Core voltage supply pin.

VDDO 7 P Output voltage supply pin for CLK0, CLK1, and CLK2. See "6.2. Power
Supply Sequencing" on page 22.

GND 8 P Ground.

*Note: I = Input, O = Output, P = Power

Rev. 0.75 27
Si5351A/B/C-B
10. Ordering Information

Si5351X B XXX

Blank = Bulk
R = Tape and Reel

GT = 10-MSOP*
GM = 20- QFN

B = Product Revision B

A = Crystal In
B = Crystal In+ VCXO
* Note: The 10 - MSOP is only C = Crystal In+ CLKIN
available in the Si5351A variant
.

Figure 22. Device Part Numbers

An evaluation kit containing ClockBuilder Desktop software and hardware enable easy evaluation of the Si5351A/B/
C. The orderable part numbers for the evaluation kits are provided in Figure 23.

Si535X XXXXX EVB

EVB = Evaluation Kit

XXXXX = B20QFN

Figure 23. Si5351A/B/C Evaluation Kit

28 Rev. 0.75
 Si5351A/B/C-B
11. Package Outlines
11.1. 20-pin QFN

Rev. 0.75 29
Si5351A/B/C-B

Table 14. 20-pin QFN Package Dimensions

Dimension Min Nom Max
A 0.80 0.85 0.90
A1 0.00 0.02 0.05
b 0.18 0.25 0.30
D 4.00 BSC
D2 2.65 2.70 2.75
e 0.50 BSC
E 4.00 BSC
E2 2.65 2.70 2.75
L 0.30 0.40 0.50
aaa 0.10
bbb 0.10
ccc 0.08
ddd 0.10
eee 0.10
Notes:
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to the JEDEC Outline MO-220, variation VGGD-8.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body
Components.

30 Rev. 0.75
 Si5351A/B/C-B
11.2. 10-Pin MSOP

Table 15. 10-MSOP Package Dimensions

Dimension Min Nom Max
A — — 1.10
A1 0.00 — 0.15
A2 0.75 0.85 0.95
b 0.17 — 0.33
c 0.08 — 0.23
D 3.00 BSC
E 4.90 BSC
E1 3.00 BSC
e 0.50 BSC
L 0.40 0.60 0.80
L2 0.25 BSC
q 0 — 8
aaa — — 0.20
bbb — — 0.25
ccc — — 0.10
ddd — — 0.08
Notes:
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to the JEDEC Solid State Outline MO-137, Variation C
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body
Components.

Rev. 0.75 31
Si5351A/B/C-B
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Please visit the Silicon Labs Technical Support web page:
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and register to submit a technical support request.

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32 Rev. 0.75