S i 5 3 5 0 C -B

F ACTORY - P ROGRAMMABLE A NY - F REQUENCY CMOS

C L O C K G ENERATOR + PLL
Features
 www.silabs.com/custom-timing  Operates from a low-cost, fixed
 Generates up to 8 non-integer-related frequency crystal: 25 or 27 MHz 10-MSOP
frequencies from 8 kHz to 160 MHz  Separate voltage supply pins:
 Exact frequency synthesis at each Core VDD: 2.5 V or 3.3 V
output (0 ppm error) Output VDDO: 1.8 V, 2.5 V, or 3.3 V
 Glitchless frequency changes  Excellent PSRR eliminates external
 Low output period jitter: < 70 ps pp, typ power supply filtering
 Configurable Spread Spectrum  Very low power consumption
selectable at each output (<45 mA)
 User-configurable control pins:  Available in 2 packages types:
20-QFN
Output Enable (OEB_0/1/2) 10-MSOP: 3 outputs
Power Down (PDN) 20-QFN (4x4 mm): 8 outputs
Frequency Select (FS_0/1)  PCIE Gen 1 compliant
Spread Spectrum Enable (SSEN)  Supports HCSL compatible swing
Loss of Lock Status (LOL)
 Supports static phase offset
 Rise/fall time control

Applications Ordering Information:

See Page 18
 HDTV, DVD/Blu-ray, set-top box  Residential gateways
 Audio/video equipment, gaming  Networking/communication
 Printers, scanners, projectors  Servers, storage
 XO replacement

Description
The Si5350C generates free-running and/or synchronized clocks selectable on each
of its outputs. A dual PLL + high resolution MultiSynthTM fractional divider
architecture enables this user-definable custom timing device to generate any of the
specified output frequencies at any of its outputs. This allows the Si5350C to replace
a combination of crystals, crystal oscillators, and synchronized clocks (PLL). Custom
pin-controlled Si5350C devices can be requested using the ClockBuilder web-based
part number utility (www.silabs.com/ClockBuilder).
20-QFN
Multi
Synth CLK0
0
XA
Multi
Synth CLK1
10-MSOP XB
OSC PLLA 1
Multi
Synth CLK2
XA 2
Multi PLLB
Synth CLK0 Multi
OSC 0 Synth CLK3
PLLA CLKIN 3
XB Multi
Synth CLK1 Multi
1 Synth CLK4
PLLB 4
Multi
CLKIN Synth CLK2 P0 Multi
2 Synth CLK5
5
P1 Control
Multi
Control Logic Synth CLK6
P0 P2
Logic 6
Si5350C P3 Multi
CLK7
Synth
7

Si5350C

Rev. 0.75 10/12 Copyright © 2012 by Silicon Laboratories Si5350C-B

This information applies to a product under development. Its characteristics and specifications are subject to change without notice.
Si5350C-B

2 Rev. 0.75
 Si5350C-B
TABLE O F C ONTENTS

Section Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Typical Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
2.1. Si5350C Replaces Multiple Clocks and XOs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
2.2. Applying a Reference Clock at XTAL Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
2.3. HCSL Compatible Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
3. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4. Configuring the Si5350C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4.1. Crystal Inputs (XA, XB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.2. External Clock Input Pin (CLKIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3. Output Clocks (CLK0–CLK7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.4. Programmable Control Pins (P0–P3) Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.5. Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5. Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1. 20-pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2. 10-pin MSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
7. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
7.1. 20-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
7.2. 10-Pin MSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Rev. 0.75 3
Si5350C-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 3.6 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
Note: 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 — 20 35 mA

Core Supply Current* IDD Enabled 8 outputs — 25 45 mA

Power Down (PDN = VDD) — — 50 µA

Output Buffer Supply 2.2 5.0

IDDOx CL = 5 pF — mA
Current (Per Output)*
Pins P1, P2, P3
IP1-P3 — — 10 µA
Input Current VP1-P3 < 3.6 V

IP0 Pin P0 — — 30 µA

3.3 V VDDO, default high

Output Impedance ZOI — 50 — 
drive.

*Note: Output clocks less than or equal to 100 MHz.

4 Rev. 0.75
 Si5350C-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, — 2 10 ms
fCLKn > 1 MHz
From VDD = VDDmin, CL = 5 pF,
Power-Down Time TPD — 5 100 ms
fCLKn > 1 MHz
From OEB assertion to valid
Output Enable Time TOE clock output, CL = 5 pF, fCLKn — — 10 µs
> 1 MHz
Output Frequency Transition
TFREQ fCLKn > 1 MHz — — 10 µs
Time
Spread Spectrum Frequency
SSDEV Down Spread –0.5 — –2.5 %
Deviation
Spread Spectrum
SSMOD_C 30 31.5 33 kHz
Modulation Rate

Table 4. Input Characteristics

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

Parameter Symbol Test Condition Min Typ Max Units

Crystal Frequency fXTAL 25 — 27 MHz
P0-P3 Input Low Voltage VIL_P0-3 –0.1 — 0.3 x VDD V
P0-P3 Input High Voltage VIH_P0-3 0.7 x VDD — 3.60 V
CLKIN Frequency Range fCLKIN 10 — 100 MHz
CLKIN Input Low Voltage VIL_CLKIN –0.1 — 0.3 x VDD V
CLKIN Input High Voltage VIH_CLKIN 0.7 x VDD — 3.60 V

Rev. 0.75 5
Si5350C-B

Table 5. Output Characteristics

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

Parameter Symbol Test Condition Min Typ Max Units

Frequency Range FCLK 0.008 — 160 MHz
Load Capacitance CL FCLK < 100 MHz — — 15 pF
Duty Cycle DC Measured at VDD/2 45 50 55 %
Rise/Fall Time tr/tf 20%–80%, CL = 5 pF — 1 1.5 ns

Output High Voltage VOH VDD – 0.6 — — V

CL = 5 pF
Output Low Voltage VOL — — 0.6 V
Period Jitter* JPER 20-QFN, 4 outputs running, ‐ 40 95 ps, pk‐pk
1 per VDDO
10-MSOP or 20-QFN, all ‐ 70 140 ps, pk‐pk
outputs running
Cycle-to-cycle Jitter* JCC 20-QFN, 4 outputs running, — 50 90 ps, pk
1 per VDDO
10-MSOP or 20-QFN, all — 70 130 ps, pk
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.

Table 6. 25 MHz Crystal Requirements1,2

Parameter Symbol Min Typ Max Unit
Crystal Frequency fXTAL — 25 — 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. Adding external 2 pF load
capacitors can minimize jitter by 20%
2. Refer to “AN551: Crystal Selection Guide” for more details.

6 Rev. 0.75
 Si5350C-B

Table 7. 27 MHz Crystal Requirements1,2

Parameter Symbol Min Typ Max Unit
Crystal Frequency fXTAL — 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. Adding external 2 pF load
capacitors can minimize jitter by 20%
2. Refer to “AN551: Crystal Selection Guide” for more details.

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 Ratings

Parameter Symbol Test Condition Value Unit
DC Supply Voltage VDD_max –0.5 to 3.8 V
VIN_P1-3 Pins P1, P2, P3 –0.5 to 3.8 V
Input Voltage VIN_P0 P0 –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
Note: Permanent device damage may occur if the absolute maximum ratings are exceeded. Functional operation should be
restricted to the conditions specified in the operational sections of this data sheet. Exposure to absolute maximum
rating conditions for extended periods may affect device reliability.

Rev. 0.75 7
Si5350C-B
2. Typical Application
2.1. Si5350C Replaces Multiple Clocks and XOs
The Si5350C is a clock generation device that provides both synchronous and free-running clocks for applications
where power, board size, and cost are critical. An example application is shown in Figure 1. Any other combination
is possible.

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

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
Si5350C
Synchronous
Clocks

Figure 1. Replacing multiple XTAL/XOs and PLLs with one Si5350C

2.2. Applying a Reference Clock at XTAL Input
The Si5350C 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; 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 2. Si5350C Driven by a Clock Signal

8 Rev. 0.75
 Si5350C-B
2.3. 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.

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 3. Si5350C Output is HCSL Compatible

Rev. 0.75 9
Si5350C-B
3. Functional Description
The architecture of the Si5350C generates up to eight non-integer-related frequencies in any combination of free-
running and/or synchronous clocks. A block diagram of both the 3-output and the 8-output versions are shown in
Figure 4. Free-running clocks are generated using the on-chip oscillator + PLL, and the clock input pin (CLKIN)
provides an external input reference for the synchronous clocks. Each MultiSynthTM is configurable with two
frequencies (F1_x, F2_x). This allows a pin controlled glitchless frequency change at each output (CLK0 to CLK5).

VDD VDDO
10-MSOP
MultiSynth 0
XA PLL F1_0
OSC R0 CLK0
A F2_0
XB FS
PLL MultiSynth 1
CLKIN B F1_1
R1 CLK1
F2_1
FS
MultiSynth 2
Control F1_2
P0 Logic R2 CLK2
F2_2
FS
MultiSynth 3

GND

VDD
20-QFN
MultiSynth 0 VDDOA
F1_0
R0
XA PLL F2_0 CLK0
OSC FS
A
XB MultiSynth 1
F1_1 CLK1
PLL R1
CLKIN B F2_1
FS
MultiSynth 2 VDDOB
F1_2
R2
F2_2
CLK2
FS
MultiSynth 3
F1_3 CLK3
R3
F2_3
FS
MultiSynth 4 VDDOC
F1_4
R4
F2_4
CLK4
FS
MultiSynth 5
P0 F1_5 CLK5
R5
F2_5
P1 FS
Control
Logic
P2 MultiSynth 6
VDDOD
F1_6 R6
P3 CLK6

MultiSynth 7 CLK7
F1_7 R7

GND

Figure 4. Block Diagrams of the Si5350C Devices with 3 and 8 outputs

10 Rev. 0.75
 Si5350C-B
4. Configuring the Si5350C
The Si5350C is a factory-programmed custom clock generator that is user definable with a simple to use web-
based utility (www.silabs.com/ClockBuilder). The ClockBuilder utility provides a simple graphical interface that
allows the user to enter input and output frequencies along with other custom features as described in the following
sections. All synthesis calculations are automatically performed by ClockBuilder to ensure an optimum
configuration. A unique part number is assigned to each custom configuration.

4.1. Crystal Inputs (XA, XB)

The Si5350C uses an optional fixed-frequency non-pullable standard AT-cut crystal as a reference to generate
free-running output clocks. Note that a XTAL is not required for generating synchronous clocks that are locked to
CLKIN.
4.1.1. Crystal Frequency
The Si5350C can operate using either a 25 MHz or a 27 MHz crystal.
4.1.2. Internal XTAL Load Capacitors
Internal load capacitors (CL) are provided to eliminate the need for external components when connecting a XTAL
to the Si5350C. Options for internal load capacitors are 6, 8, or 10 pF. XTALs with alternate load capacitance
requirements are supported using external load capacitors < 2 pF as shown in Figure 5.

CL XA

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

Figure 5. External XTAL with Optional Load Capacitors

4.2. External Clock Input Pin (CLKIN)

The external clock input is used as a reference for generating synchronous clocks. The input frequency can be
specified from 10 to 100 MHz including fractional frequencies (e.g., 74.25 MHz x 1000/1001). The ClockBuilder
utility automatically determines the exact synthesis ratio to guarantee an output frequency with 0 ppm error with
respect to its reference.

4.3. Output Clocks (CLK0–CLK7)

The Si5350C is orderable as a 3-output (10-MSOP) or 8-output (20-QFN) clock generator. Output clocks CLK0 to
CLK5 can be ordered with two clock frequencies (F1_x, F2_x) which are selectable with the optional frequency
select pins (FS0/1). See “4.4.2. Power Down (PDN)” for more details on the operation of the frequency select pins.
Each output clock can select its reference for either of the PLLs.
4.3.1. Output Clock Frequency
Outputs can be configured at any frequency from 8 kHz up to 112.5 MHz. In addition, the device can generate any
frequency up to 160 MHz on two of its outputs.
4.3.2. 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.
The Si5350C supports several levels of spread spectrum allowing the designer to choose an ideal compromise
between system performance and EMI compliance.

Rev. 0.75 11
Si5350C-B
An optional spread spectrum enable pin (SSEN) is configurable to enable or disable the spread spectrum feature.
See “4.4.1. Spread Spectrum Enable (SSEN)” for details.

Reduced
Center
Am plitude
Frequency
and EM I
Am plitude

fc fc
No Spread
D ow n Spread
Spectrum

Figure 6. Available Spread Spectrum Profiles

4.3.3. Invert/Non-Invert
By default, each of the output clocks are generated in phase (non-inverted) with respect to each other. An option to
invert any of the clock outputs is also available.
4.3.4. Output State When Disabled
There are up to three output enable pins configurable on the Si5350C as described in “4.4.4. Output Enable
(OEB_0, OEB_1, OEB_2)” . The output state when disabled for each of the outputs is configurable as output high,
output low, or high-impedance.
4.3.5. Powering Down Unused Outputs
Unused clock outputs can be completely powered down to conserve power.

4.4. Programmable Control Pins (P0–P3) Options

Up to four programmable control pins (P0-P3) are configurable allowing direct pin control of the following features:
4.4.1. Spread Spectrum Enable (SSEN)
An optional 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.
4.4.2. Power Down (PDN)
An optional power down control pin allows a full shutdown of the Si5350C to minimize power consumption when its
output clocks are not being used. The Si5350C is in normal operation when the PDN pin is held low and is in power
down mode when held high. Power consumption when the device is in power down mode is indicated in Table 2 on
page 4.
4.4.3. Frequency Select (FS_0, FS_1)
The Si5350C offers the option of configuring up to two frequencies per clock output (CLK0-CLK5) for either free-
running or synchronous clocks. This is a useful feature for applications that need to support more than one free-
running or synchronous clock rate on the same output. An example of this is shown in Figure 7. The FS pins select
which frequency is generated from the clock output. In this example, FS0 selects the output frequency on CLK0
and FS1 selects the frequency on CLK1.

12 Rev. 0.75
 Si5350C-B

27 MHz

FS0
Free-running Frequency XA XB
Bit Level
0 F1_0: 74.25 MHz
Free-running Clock
1 74.25 74.25
F2_0: MHz FS0 74.25 MHz or MHz
1.001 CLK0 1.001

Si5350C Video/Audio
FS1 Synchronous Clock
FS1 Processor
Synchronous Frequency CLK1 24.576 MHz or 22.5792 MHz
Bit Level
0 F1_1: 24.576 MHz 54MHz
CLKIN
1 F2_1: 22.5792 MHz

Figure 7. Example of Generating Two Clock Frequencies from the Same Clock Output
Up to two frequency select pins are available on the Si5350C. Each of the frequency select pins can be linked to
any of the clock outputs as shown in Figure 8. For example, FS_0 can be linked to control clock frequency
selection on CLK0, CLK3, and CLK5; FS_1 can be used to control clock frequency selection on CLK1, CLK2, and
CLK4. Any other combination is also possible.
The Si5350C uses control circuitry to ensure that frequency changes are glitchless. This ensures that the clock
always completes its last cycle before starting a new clock cycle of a different frequency.

Customizable FS Control Glitchless Frequency Changes

FS
MultiSynth 0 CLK0

FS
MultiSynth 1 CLK1 New frequency starts
FS_0 Output Frequency FS_0 at its leading edge
0 F1_0, F1_3, F1_5 FS
MultiSynth 2 CLK2
1 F2_0, F2_3, F2_5
FS Frequency_A Frequency_B Frequency_A
MultiSynth 3 CLK3

FS
CLKx
MultiSynth 4 CLK4
FS_1
FS_1 Output Frequency
0 F1_1, F1_2, F1_4 FS
MultiSynth 5 CLK5
1 F2_1, F2_2, F2_4 Full cycle completes before
CLK6 changing to a new frequency
Cannot be controlled
by FS pins
CLK7

Figure 8. Example Configuration of a Pin-Controlled Frequency Select (FS)

Rev. 0.75 13
Si5350C-B
4.4.4. Output Enable (OEB_0, OEB_1, OEB_2)
Up to three output enable pins (OEB_0/1/2) are available on the Si5350C. Similar to the FS pins, each OEB pin
can be linked to any of the output clocks. In the example shown in Figure 9, OEB_0 is linked to control CLK0,
CLK3, and CLK5; OEB_1 is linked to control CLK6 and CLK7, and OEB_2 is linked to control CLK1, CLK2, CLK4,
and CLK5. Any other combination is also possible. If more than one OEB pin is linked to the same CLK output, the
pin forcing a disable state will be dominant. Clock outputs are enabled when the OEB pin is held low.
The output enable control circuitry ensures glitchless operation by starting the output clock cycle on the first leading
edge after OEB is asserted (OEB = low). When OEB is released (OEB = high), the clock is allowed to complete its
full clock cycle before going into a disabled state. This is shown in Figure 9. When disabled, the output state is
configurable as disabled high, disabled low, or disabled in high-impedance.

Customizable OEB Control Glitchless Output Enable

CLK0
OEB
OEB_0 Output State OEB_0
0 CLK Enabled CLK1
OEB
1 CLK Disabled
Clock starts on the Clock continues until
CLK2
first leading edge cycle is complete
OEB

CLK3
OEB_1 Output State OEB_1 OEB CLKx
0 CLK Enabled
1 CLK Disabled CLK4
OEB OEBx
CLK5
OEB

OEB_2 Output State CLK6

OEB_2 OEB
0 CLK Enabled
1 CLK Disabled CLK7
OEB

Figure 9. Example Configuration of a Pin-Controlled Output Enable

4.4.5. Loss Of Lock (LOL)
A loss of lock pin (LOL) is available to indicate the status of the synchronous clock outputs. The LOL pin is set to a
low state when the synchronous clock outputs are locked to the clock input (CLKIN). This is the normal operating
state for the synchronous clocks. The LOL pin will go high when the reference clock at the CLKIN input is removed
or if its frequency deviates by more than 2000 ppm from its defined center frequency. In this case, the synchronous
clocks will continue to free-run. An option to disable the synchronous output clocks during an LOL condition (LOL
pin = high) is available. This only affects the clock outputs that were designated as synchronous clock outputs.

4.5. Design Considerations

The Si5350C is a self-contained clock generator that requires very few external components. The following general
guidelines are recommended to ensure optimum performance.
4.5.1. Power Supply Decoupling/Filtering
The Si5350C has built-in power supply filtering circuitry to help keep the number of external components to a
minimum. 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 VDDO pins as possible without using vias.
4.5.2. 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 or at the same time as VDD. Unused VDDOx pins should be tied to VDD.
4.5.3. 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.

14 Rev. 0.75
 Si5350C-B
4.5.4. External Crystal Load Capacitors
The Si5350C provides the option of using internal and external crystal load capacitors. 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.
4.5.5. Unused Pins
Unused control pins (P0–P3) should be tied to GND.
Unused CLKIN pin should be tied to GND.
Unused XA/XB pins should be left floating. Refer to "2.2. Applying a Reference Clock at XTAL Input" on page 8
when using XA as a clock input pin.
Unused output pins (CLK0–CLK7) should be left unconnected.
4.5.6. Trace Characteristics
The Si5350C features various output drive strength settings. It is recommended to configure the trace
characteristics as shown in Figure 10 when the default high output drive setting is used.

ZO = 50 ohms

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

Figure 10. Recommended Trace Characteristics with Default Drive Strength Setting
Note: Jitter is only specified at default high drive strength.

Rev. 0.75 15
Si5350C-B
5. Pin Descriptions
5.1. 20-pin QFN

18 VDDOC
19 CLK4

17 CLK5

16 CLK6
20 VDD
XA 1 15 CLK7

XB 2 14 VDDOD
GND
P0 3 PAD 13 CLK0

P1 4 12 CLK1

P2 5 11 VDDOA

VDDOB 10
7

9
8
6
CLKIN

CLK3
P3

CLK2
Figure 11. Si5350C 20-QFN Top View

Table 10. Si5350C 20-QFN Pin Descriptions

Pin Name Pin Number Pin Type Function
XA 1 I Input pin for external XTAL
XB 2 I Input pin for external XTAL
CLKIN 6 I External reference clock input
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
P0 3 I User configurable input pin 0. See 4.5.5
P1 4 I User configurable input pin 1. See 4.5.5
P2 5 I User configurable input pin 2. See 4.5.5
P3 7 I User configurable input pin 3. See 4.5.5
VDD 20 P Core voltage supply pin. See 4.5.2
VDDOA 11 P Output voltage supply pin for CLK0 and CLK1. See 4.5.2
VDDOB 10 P Output voltage supply pin for CLK2 and CLK3. See 4.5.2
VDDOC 18 P Output voltage supply pin for CLK4 and CLK5. See 4.5.2
VDDOD 14 P Output voltage supply pin for CLK6 and CLK7. See 4.5.2
GND Center Pad P Ground
Note: Pin Types: I = Input, O = Output, P = Power

16 Rev. 0.75
 Si5350C-B
5.2. 10-pin MSOP

VDD 1 10 CLK0

XA 2 9 CLK1

XB 3 8 GND

P0 4 7 VDDO

CLKIN 5 6 CLK2

Figure 12. Si5350C 10-MSOP Top View

Table 11. Si5350C 10-MSOP Pin Descriptions

Pin Name Pin Number Pin Type Function
XA 2 I Input pin for external XTAL
XB 3 I Input pin for external XTAL
CLKIN 5 I External reference clock input
CLK0 10 O Output clock 0
CLK1 9 O Output clock 1
CLK2 6 O Output clock 2
P0 4 I User configurable input pin 0. See 4.5.5
VDD 1 P Core voltage supply pin. See 4.5.2
VDDO 7 P Output voltage supply pin for CLK0, CLK1, and CLK2. See 4.5.2
GND 8 P Ground
Note: Pin Types: I = Input, O = Output, P = Power

Rev. 0.75 17
Si5350C-B
6. Ordering Information
Factory-programmed Si5350C devices can be requested using the ClockBuilder web-based utility available at:
www.silabs.com/ClockBuilder. A unique part number is assigned to each custom configuration as indicated in
Figure 13.

Si5350A BXXXXX XXX

Blank = Bulk
R = Tape and Reel

GT =10-MSOP
GM =20-QFN

B = Product Revision B
XXXXX = Unique Custom Code . A five character code will be
assigned for each unique custom configuration

Figure 13. Custom Clock Part Numbers

18 Rev. 0.75
 Si5350C-B
7. Package Outline
7.1. 20-Pin QFN

Figure 14. 20-pin QFN Package Drawing

Table 12. 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.

Rev. 0.75 19
Si5350C-B
7.2. 10-Pin MSOP
 

Figure 15. 10-pin MSOP Package Drawing

Table 13. 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.

20 Rev. 0.75
 Si5350C-B
NOTES:

Rev. 0.75 21
Si5350C-B
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22 Rev. 0.75