Si5347/46 Data Sheet

S i 5 3 4 7/46
D U AL /Q UA D DSPLL A NY - F RE QU EN CY, A NY -O UT P UT J ITTER A TT E NU AT OR S
Features











Four or two independent DSPLLs in a
single monolithic IC
Each DSPLL generates any output
frequency from any input frequency
Input frequency range:
Differential: 8 kHz to 750 MHz
LVCMOS: 8 kHz to 250 MHz
Output frequency range:
Differential: up to 712.5 MHz
LVCMOS: up to 250 MHz
Ultra low jitter:
<100 fs typ (12 kHz–20 MHz)
Flexible crosspoints route any input to
any output clock
Programmable jitter attenuation
bandwidth per DSPLL: 0.1 Hz to 4 kHz
programming range
Highly configurable outputs compatible
with LVDS, LVPECL, LVCMOS, CML,
and HCSL with programmable signal
amplitude
Status monitoring (LOS, OOF, LOL)
Hitless input clock switching: automatic
or manual
Locks to gapped clock inputs




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

Automatic free-run and holdover modes
Fastlock feature for low nominal
bandwidths
Glitchless on-the-fly DSPLL frequency
changes
DCO mode: as low as 0.01 ppb steps
per DSPLL
Core voltage:
VDD: 1.8 V ±5%
VDDA: 3.3 V ±5%
Independent output clock supply pins:
3.3, 2.5, or 1.8 V
Output-output skew:
<20 ps (typ) per DSPLL


Serial interface: I2C or SPI
In-circuit programmable with non-volatile
OTP memory

ClockBuilderTM Pro software tool
simplifies device configuration
Si5347: Quad DSPLL, 4 input,
4 or 8 output, 64 QFN
Si5346: Dual DSPLL, 4 input,
4 output, 44 QFN
Temperature range: –40 to +85 °C
Pb-free, RoHS-6 compliant

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
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9x9 mm
Ordering Information:
See section 8
Functional Block Diagram
XTAL/
REFCLK
Si5347
Max Output Freq
Frequency Synthesis Modes
4/8
712.5 MHz
Integer + Fractional
Si5347C
4/4
712.5 MHz
Integer + Fractional
Si5346A
2/4
712.5 MHz
Integer + Fractional
Si5347B
4/8
350 MHz
Integer + Fractional
Si5347D
4/4
350 MHz
Integer + Fractional
Si5346B
2/4
350 MHz
Integer + Fractional
IN0
÷FRAC
DSPLL
A
IN1
÷FRAC
DSPLL
B
IN2
÷FRAC
DSPLL
C
IN3
÷FRAC
DSPLL
D
NVM
OTN Muxponders and Transponders
10/40/100G network line cards
GbE/10 GbE/100 GbE Synchronous
Ethernet (ITU-T G.8262)
OUT0
÷INT
OUT1
÷INT
OUT2
÷INT
OUT3
÷INT
OUT4
÷INT
OUT5
÷INT
OUT6
÷INT
OUT7
I2C/SPI
Control/
Status
Applications



÷INT
Si5347A/B
PLLs/OUTs
XB
Si5347C/D
Grade
XA
OSC
Device Selector Guide
Si5347A
7x7 mm


Carrier Ethernet switches
Broadcast video
XTAL/
R EFC LK
S i5 3 4 6
XA
XB
OSC
Description
IN 0
The Si5347 is a high performance jitter attenuating clock multiplier which integrates four
any-frequency DSPLLs for applications that require maximum integration and independent
timing paths. The Si5346 is a dual DSPLL version in a smaller package. Each DSPLL has
access to any of the four inputs and can provide low jitter clocks on any of the device
outputs. Based on 4th generation DSPLL technology, these devices provide any-frequency
conversion with typical jitter performance under 100 fs. Each DSPLL supports independent
free-run, holdover modes of operation, as well as automatic and hitless input clock
switching. The Si5347/46 is programmable via a serial interface with in-circuit
programmable non-volatile memory so that it always powers up in a known configuration.
Programming the Si5347/46 is easy with Silicon Labs’ ClockBuilder Pro software. Factory
pre-programmed devices are also available.
Rev. 1.1 9/15
IN 1
÷FR A C
÷FR A C
IN 2
÷FR A C
IN 3
÷FR A C
Copyright © 2015 by Silicon Laboratories
DSPLL
A
DSPLL
B
÷ IN T
OUT0
÷ IN T
OUT1
÷ IN T
OUT2
÷ IN T
OUT3
NVM
I 2 C /S P I
C o n tro l/
S ta tu s
Si5347/46
Si5347/46
TABLE O F C ONTENTS
1. Typical Application Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
2. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
3. Typical Operating Characteristics (Jitter and Phase Noise) . . . . . . . . . . . . . . . . . . . . . 22
4. Detailed Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
5. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.1. Frequency Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.2. DSPLL Loop Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.3. Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.4. Digitally-Controlled Oscillator (DCO) Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.5. External Reference (XA/XB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.6. Inputs (IN0, IN1, IN2, IN3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.7. Fault Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
5.8. Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
5.9. Power Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.10. In-Circuit Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.11. Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
5.12. Custom Factory Preprogrammed Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.13. How to Enable Features and/or Configuration Settings Not Available in
ClockBuilder Pro for Factory Pre-programmed Devices . . . . . . . . . . . . . . . . . . . . . . . . . 42
6. Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
7. Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
8. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
8.1. Ordering Part Number Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
9. Package Outlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
9.1. Si5347 9x9 mm 64-QFN Package Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
9.2. Si5346 7x7 mm 44-QFN Package Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
10. PCB Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
11. Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
12. Device Errata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
2
Rev. 1.1
Si5347/46
1. Typical Application Schematic
OTN Muxponder
Si5347
Client #1
Data
Clock
PD
÷
Gapped Clock
PHY
10GbE
PHY
10GbE
PHY
10GbE
PHY
10GbE
LPF
Mn_A
Md_A
DSPLL A
Non-gapped
Jitter Attenuated Clock
Client #2
Data
Clock
40G OTN
PD
LPF
÷
Gapped Clock
Mn_B
Md_B
DSPLL B
OTN
De-Mapper
Non-gapped
Jitter Attenuated Clock
Client #3
Data
Clock
PD
LPF
÷
Gapped Clock
Mn_C
Md_C
DSPLL C
Non-gapped
Jitter Attenuated Clock
Client #4
Data
Clock
PD
Gapped Clock
LPF
÷
Mn_D
Md_D
DSPLL D
Non-gapped
Jitter Attenuated Clock
Figure 1. Using the Si5347 to Clean Gapped Clocks in an OTN Application
Rev. 1.1
3
Si5347/46
2. Electrical Specifications
Table 1. Recommended Operating Conditions
(VDD = 1.8 V ±5%, VDDA = 3.3 V ±5%,TA = –40 to 85 °C)
Parameter
Symbol
Min
Typ
Max
Unit
Ambient Temperature
TA
–40
25
85
°C
Junction Temperature
TJMAX
—
—
125
°C
Core Supply Voltage
VDD
1.71
1.80
1.89
V
VDDA
3.14
3.30
3.47
V
VDDO
3.14
3.30
3.47
V
2.38
2.50
2.62
V
1.71
1.80
1.89
V
3.14
3.30
3.47
V
1.71
1.80
1.89
V
Output Driver Supply Voltage
Status Pin Supply Voltage
VDDS
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.
Table 2. DC Characteristics
(VDD = 1.8 V ±5%, VDDA = 3.3 V ±5%, VDDO = 1.8 V ±5%, 2.5 V ±5%, or 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Core Supply Current
Test Condition
IDD
Min
Typ
Max
Unit
—
175
240
mA
Si5346
—
170
230
mA
Si5347
—
120
130
mA
120
130
mA
Si5347
IDDA
Notes 1, 2
Si5346
Notes:
1. Si5347 test configuration: 7 x 2.5 V LVDS outputs enabled @156.25 MHz. Excludes power in termination resistors.
2. Si5346 test configuration: 4 x 2.5 V LVDS outputs enabled @ 156.25 MHz. Excludes power in termination resistors.
3. Differential outputs terminated into an AC coupled 100  load.
4. LVCMOS outputs measured into a 5-inch 50  PCB trace with 5 pF load. The LVCMOS outputs were set to
OUTx_CMOS_DRV = 3, which is the strongest driver setting. Refer to the Si5347/46 Family Reference Manual for
more details on register settings.
5. Detailed power consumption for any configuration can be estimated using ClockBuilder Pro when an evaluation board
(EVB) is not available. All EVBs support detailed current measurements for any configuration.
LVCMOS Output Test Configuration
Differential Output Test Configuration
Trace length 5
inches
IDDO
0.1 µF
OUT
IDDO
50
100
OUT
499 
0.1 µF
50  Scope Input
50
OUT
4.7 pF
56 
OUT
50
0.1 µF
499 
0.1 µF
50  Scope Input
50
4.7 pF
4
Rev. 1.1
56 
Si5347/46
Table 2. DC Characteristics (Continued)
(VDD = 1.8 V ±5%, VDDA = 3.3 V ±5%, VDDO = 1.8 V ±5%, 2.5 V ±5%, or 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
IDDO
LVPECL Output3
@ 156.25 MHz
—
21
25
mA
LVDS Output3
@ 156.25 MHz
—
15
18
mA
3.3V LVCMOS4 output
@ 156.25 MHz
—
21
25
mA
2.5V LVCMOS4 output
@ 156.25 MHz
—
16
18
mA
1.8V LVCMOS4 output
@ 156.25 MHz
—
12
13
mA
Output Buffer Supply Current
Total Power Dissipation
Pd
Si5347
Note 1,5
—
980
1160
mW
Si5346
Note 2,5
—
840
1000
mW
Notes:
1. Si5347 test configuration: 7 x 2.5 V LVDS outputs enabled @156.25 MHz. Excludes power in termination resistors.
2. Si5346 test configuration: 4 x 2.5 V LVDS outputs enabled @ 156.25 MHz. Excludes power in termination resistors.
3. Differential outputs terminated into an AC coupled 100  load.
4. LVCMOS outputs measured into a 5-inch 50  PCB trace with 5 pF load. The LVCMOS outputs were set to
OUTx_CMOS_DRV = 3, which is the strongest driver setting. Refer to the Si5347/46 Family Reference Manual for
more details on register settings.
5. Detailed power consumption for any configuration can be estimated using ClockBuilder Pro when an evaluation board
(EVB) is not available. All EVBs support detailed current measurements for any configuration.
LVCMOS Output Test Configuration
Differential Output Test Configuration
Trace length 5
inches
IDDO
0.1 µF
OUT
IDDO
50
100
OUT
499 
0.1 µF
50  Scope Input
50
OUT
4.7 pF
56 
OUT
50
0.1 µF
499 
0.1 µF
50  Scope Input
50
4.7 pF
Rev. 1.1
56 
5
Si5347/46
Table 3. Input Specifications
(VDD = 1.8 V ±5%, VDDA = 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Standard Differential or Single-Ended/LVCMOS — AC-coupled (IN0, IN1, IN2, IN3/FB_IN)
Input Frequency Range
Input Voltage Swing
Input Voltage Amplitude
fIN_DIFF
VIN_DIFF
VIN_SE
Differential
0.008
—
750
MHz
Single-ended/LVCMOS
0.008
—
250
fIN< 250 MHz, Differential
100
—
1800
mVpp_se
250 MHz < fIN< 750 MHz,
Differential
225
—
1800
mVpp_se
fIN< 250 MHz, Singleended
100
—
3600
mVpp_se
Slew Rate1,2
SR
400
—
—
V/µs
Duty Cycle
DC
40
—
60
%
Capacitance
CIN
—
2
—
pF
0.008
—
250
MHz
VIL
–0.2
—
0.33
V
VIH
0.49
—
—
V
SR
400
—
—
V/µs
1.6
—
—
ns
—
8
—
k
48
—
54
MHz
Pulsed CMOS — DC-coupled (IN0, IN1, IN2, IN3)3
Input Frequency
fIN_PULSED
Input Voltage
Slew
Rate1,2
Minimum Pulse Width
PW
Input Resistance
RIN
Pulse Input
REFCLK (Applied to XA/XB)
REFCLK Frequency
fIN_REF
Input Voltage Swing
VIN_DIFF
365
—
2500
mVpp_diff
VIN_SE
365
—
2000
mVpp_se
400
—
—
V/µs
40
—
60
%
Slew rate1,2
SR
Input Duty Cycle
DC
Frequency range for best
output jitter performance
Imposed for best jitter performance
Notes:
1. Imposed for jitter performance.
2. Rise and fall times can be estimated using the following simplified equation: tr/tf80-20 = ((0.8 - 0.2) x VIN_Vpp_se) / SR.
3. Pulsed CMOS mode is intended primarily for single-ended LVCMOS input clocks < 1 MHz, which must be dc-coupled
because they have a duty cycle significantly less than 50%. A typical application example is a low frequency video
frame sync pulse. Since the input thresholds (VIL, VIH) of this buffer are non-standard (0.33 and 0.49 V, respectively),
refer to the input attenuator circuit for DC-coupled Pulsed LVCMOS in the Si5347-46 Family Reference Manual.
Otherwise, for standard LVCMOS input clocks, use the Standard AC-coupled, Single-ended input mode.
6
Rev. 1.1
Si5347/46
Table 4. Serial and Control Input Pin Specifications
(VDD = 1.8 V ±5%, VDDA = 3.3 V ±5%, VDDS = 3.3 V ±5%, 1.8 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Si5347 Serial and Control Input Pins (I2C_SEL, RST, OE0, A1/SDO, SCLK, A0/CS, FINC, A0/CS, SDA/SDIO,
DSPLL_SEL[1:0])
VIL
—
—
0.3 x VDDIO1
V
VIH
0.7 x
VDDIO1
—
—
V
Input Capacitance
CIN
—
2
—
pF
Input Resistance
RL
—
20
—
k
Minimum Pulse Width
PW
RST, FINC
100
—
—
ns
Update Rate
FUR
FINC
—
—
1
MHz
VIL
—
—
0.3 x VDDS
V
VIH
0.7 x VDDS
—
—
V
Input Capacitance
CIN
—
2
—
pF
Minimum Pulse Width
PW
FDEC
100
—
—
ns
Update Rate
FUR
FDEC
—
—
1
MHz
Input Voltage
Si5347 Control Input Pins (FDEC, OE1)
Input Voltage
Si5346 Serial and Control Input Pins (I2C_SEL, RST, OE0, OE1, A1/SDO, SCLK, A0/CS, SDA/SDIO)
VIL
—
—
0.3 x VDDIO1
V
VIH
0.7 x
VDDIO1
—
—
V
Input Capacitance
CIN
—
2
—
pF
Input Resistance
RL
—
20
—
k
Minimum Pulse Width
PW
100
—
—
ns
Input Voltage
RST
Note:
1. VDDIO is determined by the IO_VDD_SEL bit. It is selectable as VDDA or VDD.
Rev. 1.1
7
Si5347/46
Table 5. Differential Clock Output Specifications
(VDD = 1.8 V ±5%, VDDA = 3.3V ±5%, VDDO = 1.8 V ±5%, 2.5 V ±5%, or 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Output Frequency
fOUT
Duty Cycle
DC
Output-Output Skew
Test Condition
Min
Typ
Max
Unit
0.0001
—
712.5
MHz
fOUT < 400 MHz
48
—
52
%
400 MHz < fOUT < 712.5 MHz
44
—
55
%
Differential Output,
Normal Swing Mode
—
20
50
ps
Differential Output,
Low Power Swing Mode
—
20
100
ps
Measured from the positive to
negative output pins
—
0
100
ps
mVpp_se
TSK
OUT-OUT Skew
TSK_OUT
Output Voltage Amplitude1
Normal Mode
VOUT
VDDO = 3.3 V,
2.5 V, or 1.8 V
LVDS
350
470
550
VDDO = 3.3 V,
2.5 V
LVPECL
660
810
1000
VDDO = 3.3 V,
2.5 V, or 1.8 V
LVDS
300
420
530
VDDO = 3.3 V,
2.5 V
LVPECL
620
820
1060
Low Power Mode
VOUT
mVpp_se
Notes:
1. Output amplitude and common mode voltage are programmable through register settings and can be stored in NVM.
Each output driver can be programmed independently. The typical normal mode (or low power mode) LVDS maximum
is 100 mV (or 80 mV) higher than the TIA/EIA-644 maximum.Refer to the Si5347/46 Family Reference Manual for
more suggested output settings. Not all combinations of voltage amplitude and common mode voltages settings are
possible.
2. Driver output impedance depends on selected output mode (Normal, Low Power). Refer to the Si5347/46 Family
Reference Manual for more information.
3. Measured for 156.25 MHz carrier frequency. Sinewave noise added to VDDO (1.8 V = 50 mVpp, 2.5 V/
3.3 V = 100 mVpp) and noise spur amplitude measured.
4. Measured across two adjacent outputs, both in LVDS mode, with the victim running at 155.52 MHz and the aggressor
at 156.25 MHz. Refer to application note, “AN862: Optimizing Si534x Jitter Performance in Next Generation Internet
Infrastructure Systems”, guidance on crosstalk minimization. Note that all active outputs must be terminated when
measuring crosstalk.
OUTx
Vcm
Vpp_se
Vcm
Vpp_se
Vpp_diff = 2*Vpp_se
OUTx
8
Rev. 1.1
Si5347/46
Table 5. Differential Clock Output Specifications (Continued)
(VDD = 1.8 V ±5%, VDDA = 3.3V ±5%, VDDO = 1.8 V ±5%, 2.5 V ±5%, or 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Common Mode Voltage1,2,3
Test Condition
Min
Typ
Max
Unit
LVDS
1.10
1.25
1.35
V
LVPECL
1.90
2.05
2.15
VDDO = 2.5 V
LVPECL,
LVDS
1.15
1.25
1.35
VDDO = 1.8 V
sub-LVDS
0.87
0.93
1.00
Normal Mode
—
170
240
Low Power Mode
—
300
430
Normal Mode
—
100
—

Low Power Mode
—
650
—

Normal Mode or Low Power Modes
VCM
Rise and Fall Times
(20% to 80%)
VDDO = 3.3 V
tR/tF
Differential Output Impedance2
ZO
ps
Notes:
1. Output amplitude and common mode voltage are programmable through register settings and can be stored in NVM.
Each output driver can be programmed independently. The typical normal mode (or low power mode) LVDS maximum
is 100 mV (or 80 mV) higher than the TIA/EIA-644 maximum.Refer to the Si5347/46 Family Reference Manual for
more suggested output settings. Not all combinations of voltage amplitude and common mode voltages settings are
possible.
2. Driver output impedance depends on selected output mode (Normal, Low Power). Refer to the Si5347/46 Family
Reference Manual for more information.
3. Measured for 156.25 MHz carrier frequency. Sinewave noise added to VDDO (1.8 V = 50 mVpp, 2.5 V/
3.3 V = 100 mVpp) and noise spur amplitude measured.
4. Measured across two adjacent outputs, both in LVDS mode, with the victim running at 155.52 MHz and the aggressor
at 156.25 MHz. Refer to application note, “AN862: Optimizing Si534x Jitter Performance in Next Generation Internet
Infrastructure Systems”, guidance on crosstalk minimization. Note that all active outputs must be terminated when
measuring crosstalk.
OUTx
Vcm
Vpp_se
Vcm
Vpp_se
Vpp_diff = 2*Vpp_se
OUTx
Rev. 1.1
9
Si5347/46
Table 5. Differential Clock Output Specifications (Continued)
(VDD = 1.8 V ±5%, VDDA = 3.3V ±5%, VDDO = 1.8 V ±5%, 2.5 V ±5%, or 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Power Supply Noise Rejection3
PSRR
Test Condition
Min
Typ
Max
Unit
10 kHz sinusoidal noise
—
–93
—
dBc
100 kHz sinusoidal noise
—
–93
—
500 kHz sinusoidal noise
—
–84
—
1 MHz sinusoidal noise
—
–79
—
10 kHz sinusoidal noise
—
–98
—
100 kHz sinusoidal noise
—
–95
—
500 kHz sinusoidal noise
—
–84
—
1 MHz sinusoidal noise
—
–76
—
Si5347
—
–75
—
dB
Si5346
—
–85
—
dB
Normal Mode
Low Power Mode
Output-output Crosstalk4
XTALK
dBc
Notes:
1. Output amplitude and common mode voltage are programmable through register settings and can be stored in NVM.
Each output driver can be programmed independently. The typical normal mode (or low power mode) LVDS maximum
is 100 mV (or 80 mV) higher than the TIA/EIA-644 maximum.Refer to the Si5347/46 Family Reference Manual for
more suggested output settings. Not all combinations of voltage amplitude and common mode voltages settings are
possible.
2. Driver output impedance depends on selected output mode (Normal, Low Power). Refer to the Si5347/46 Family
Reference Manual for more information.
3. Measured for 156.25 MHz carrier frequency. Sinewave noise added to VDDO (1.8 V = 50 mVpp, 2.5 V/
3.3 V = 100 mVpp) and noise spur amplitude measured.
4. Measured across two adjacent outputs, both in LVDS mode, with the victim running at 155.52 MHz and the aggressor
at 156.25 MHz. Refer to application note, “AN862: Optimizing Si534x Jitter Performance in Next Generation Internet
Infrastructure Systems”, guidance on crosstalk minimization. Note that all active outputs must be terminated when
measuring crosstalk.
OUTx
Vcm
Vpp_se
Vcm
Vpp_se
Vpp_diff = 2*Vpp_se
OUTx
10
Rev. 1.1
Si5347/46
Table 6. LVCMOS Clock Output Specifications
(VDD = 1.8 V ±5%, VDDA = 3.3 V ±5%, VDDO = 1.8 V ±5%, 2.5 V ±5%, or 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Output Frequency
fOUT
Duty Cycle
DC
Output-to-Output Skew
TSK
Output Voltage High1, 2, 3
VOH
Test Condition
Min
Typ
Max
Unit
0.0001
—
250
MHz
fOUT <100 MHz
47
—
53
%
100 MHz < fOUT < 250 MHz
44
—
55
LVCMOS outputs
—
—
100
ps
VDDO x
0.75
—
—
V
—
—
—
—
—
—
—
—
—
—
—
—
—
—
VDDO = 3.3 V
OUTx_CMOS_DRV=1
IOH = –10 mA
OUTx_CMOS_DRV=2
IOH = –12 mA
OUTx_CMOS_DRV=3
IOH = –17 mA
VDDO = 2.5 V
OUTx_CMOS_DRV=1
IOH = –6 mA
OUTx_CMOS_DRV=2
IOH = –8 mA
OUTx_CMOS_DRV=3
IOH = –11 mA
VDDO x
0.75
V
VDDO = 1.8 V
OUTx_CMOS_DRV=2
IOH = –4 mA
OUTx_CMOS_DRV=3
IOH = –5 mA
VDDO x
0.75
V
Notes:
1. Driver strength is a register programmable setting and stored in NVM. Options are OUTx_CMOS_DRV = 1, 2, 3. Refer
to the Si5347/46 Family Reference Manual for more details on register settings.
2. IOL/IOH is measured at VOL/VOH as shown in the dc test configuration.
3. A 5 pF capacitive load is assumed. The LVCMOS outputs were set to OUTx_CMOS_DRV = 3.
LVCMOS Output Test Configuration
DC Test Configuration
Trace length 5
inches
IOL/IOH
IDDO
Zs
VOL/VOH
499 
0.1 µF
50  Scope Input
50
OUT
4.7 pF
56 
OUT
499 
0.1 µF
50  Scope Input
50
4.7 pF
Rev. 1.1
56 
11
Si5347/46
Table 6. LVCMOS Clock Output Specifications (Continued)
(VDD = 1.8 V ±5%, VDDA = 3.3 V ±5%, VDDO = 1.8 V ±5%, 2.5 V ±5%, or 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Output Voltage Low1, 2, 3
VOL
Test Condition
Min
Typ
Max
Unit
VDDO
x 0.15
V
VDDO
x 0.15
V
VDDO
x 0.15
V
VDDO = 3.3 V
OUTx_CMOS_DRV=1
IOL = 10 mA
—
—
OUTx_CMOS_DRV=2
IOL = 12 mA
—
—
OUTx_CMOS_DRV=3
IOL = 17 mA
—
—
VDDO = 2.5 V
OUTx_CMOS_DRV=1
IOL = 6 mA
—
—
OUTx_CMOS_DRV=2
IOL = 8 mA
—
—
OUTx_CMOS_DRV=3
IOL = 11 mA
—
—
VDDO = 1.8 V
LVCMOS Rise and Fall
Times3
(20% to 80%)
OUTx_CMOS_DRV=2
IOL = 4 mA
—
—
OUTx_CMOS_DRV=3
IOL = 5 mA
—
—
VDDO = 3.3V
—
420
550
ps
VDDO = 2.5 V
—
475
625
ps
VDDO = 1.8 V
—
525
705
ps
tr/tf
Notes:
1. Driver strength is a register programmable setting and stored in NVM. Options are OUTx_CMOS_DRV = 1, 2, 3. Refer
to the Si5347/46 Family Reference Manual for more details on register settings.
2. IOL/IOH is measured at VOL/VOH as shown in the dc test configuration.
3. A 5 pF capacitive load is assumed. The LVCMOS outputs were set to OUTx_CMOS_DRV = 3.
LVCMOS Output Test Configuration
DC Test Configuration
Trace length 5
inches
IOL/IOH
IDDO
Zs
VOL/VOH
499 
0.1 µF
50  Scope Input
50
OUT
4.7 pF
56 
OUT
499 
0.1 µF
50  Scope Input
50
4.7 pF
12
Rev. 1.1
56 
Si5347/46
Table 7. Output Serial and Status Pin Specifications
(VDD = 1.8 V ±5%, VDDA = 3.3 V ±5%, VDDS = 3.3 V ±5%, 1.8 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Si5347 Serial and Status Output Pins (LOL_A, LOL_B, LOL_C, LOL_D, INTR, LOS_XAXB, SDA/SDIO1, A1/
SDO)
Output Voltage
VOH
IOH = –2 mA
VDDIO2 x 0.75
—
—
V
VOL
IOL = 2 mA
—
—
VDDIO2 x 0.15
V
Si5346 Status Output Pins (INTR, LOS_XAXB, SDA/SDIO1, A1/SDO)
Output Voltage
VOH
IOH = –2 mA
VDDIO2 x 0.75
—
—
V
VOL
IOL = 2 mA
—
—
VDDIO2 x 0.15
V
Si5346 Serial and Status Output Pins (LOL_A, LOL_B)
Output Voltage
VOH
IOH = –2 mA
VDDS x 0.75
—
—
V
VOL
IOL = 2 mA
—
—
VDDS x 0.15
V
Notes:
1. The VOH specification does not apply to the open-drain SDA/SDIO output when the serial interface is in I2C mode or is
unused with I2C_SEL pulled high. VOL remains valid in all cases.
2. VDDIO is determined by the IO_VDD_SEL bit. It is selectable as VDDA or VDD. Users normally select this option in the
ClockBuilder Pro GUI. Alternatively, refer to the Si5347-46 Family Reference Manual for more details on register
settings.
Rev. 1.1
13
Si5347/46
Table 8. Performance Characteristics
(VDD = 1.8 V ±5%, or 3.3 V ±5%, VDDA = 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
PLL Loop Bandwidth
Programming Range3
Initial Start-Up Time
Symbol
Test Condition
fBW
Min
Typ
Max
Unit
0.1
—
4000
Hz
tSTART
Time from power-up to when the
device generates free-running clocks
—
30
45
ms
PLL Lock Time
tACQ
With Fastlock enabled,
fIN = 19.44 MHz1
—
500
600
ms
POR to Serial Interface
Ready2
tRDY
—
—
15
ms
Jitter Peaking
JPK
Measured with a frequency plan running a 25 MHz input, 25 MHz output,
and a loop bandwidth of 4 Hz
—
—
0.1
dB
Jitter Tolerance
JTOL
Compliant with G.8262 Options 1&2
Carrier Frequency = 10.3125 GHz
Jitter Modulation Frequency = 10 Hz
—
3180
—
UI pk-pk
tSWITCH
Only valid for a single switch between
two input clocks running at the same
frequency
—
—
2.8
ns
P
—
500
—
ppm
tIODELAY
—
2
—
ns
—
0.090
0.165
ps RMS
Maximum Phase
Transient During a
Hitless Switch
Pull-in Range
Input-to-Output Delay
Variation
RMS Phase Jitter4
JGEN
12 kHz to 20 MHz
Notes:
1. Lock Time can vary significantly depending on several parameters, such as bandwidths, LOL thresholds, etc. For this
case, lock time was measured with nominal and fastlock bandwidths, both set to 100 Hz, LOL set/clear thresholds of 3/
0.3 ppm respectively, using IN0 as clock reference by removing the reference and enabling it again, then measuring the
delta time between the first rising edge of the clock reference and the LOL indicator de-assertion.
2. Measured as time from valid VDD/VDDA rails (90% of their value) to when the serial interface is ready to respond to
commands.
3. Actual loop bandwidth might be lower; please refer to CBPro for actual value on your frequency plan.
4. Jitter generation test conditions: fIN = 19.44 MHz, fOUT = 156.25 MHz LVPECL, loop bandwidth = 100 Hz.
Does not include jitter from input reference.
14
Rev. 1.1
Si5347/46
Table 9. I2C Timing Specifications (SCL,SDA)
Parameter
SCL Clock
Frequency
SMBus Timeout
Symbol
Test Condition
fSCL
—
When Timeout is
Enabled
Standard Mode
100 kbps
Fast Mode
400 kbps
Unit
Min
Max
Min
Max
—
100
—
400
kHz
25
35
25
35
ms
Hold Time (repeated)
START Condition
tHD:STA
4.0
—
0.6
—
µs
Low Period of the SCL
Clock
tLOW
4.7
—
1.3
—
µs
HIGH Period of the SCL
Clock
tHIGH
4.0
—
0.6
—
µs
Set-up Time for a
Repeated START Condition
tSU:STA
4.7
—
0.6
—
µs
Data Hold Time
tHD:DAT
100
—
100
—
ns
Data Set-up Time
tSU:DAT
250
—
100
—
ns
Rise Time of Both SDA
and SCL Signals
tr
—
1000
20
300
ns
Fall Time of Both SDA and
SCL Signals
tf
—
300
—
300
ns
tSU:STO
4.0
—
0.6
—
µs
tBUF
4.7
—
1.3
—
µs
Data Valid Time
tVD:DAT
—
3.45
—
0.9
µs
Data Valid Acknowledge
Time
tVD:ACK
—
3.45
—
0.9
µs
Set-up Time for STOP
Condition
Bus Free Time between a
STOP and START Condition
Rev. 1.1
15
Si5347/46
Figure 2. I2C Serial Port Timing Standard and Fast Modes
16
Rev. 1.1
Si5347/46
Table 10. SPI Timing Specifications (4-Wire)
(VDD = 1.8 V ±5%, VDDA = 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Min
Typ
Max
Unit
SCLK Frequency
fSPI
—
—
20
MHz
SCLK Duty Cycle
TDC
40
—
60
%
SCLK Period
TC
50
—
—
ns
Delay Time, SCLK Fall to SDO Active
TD1
—
—
18
ns
Delay Time, SCLK Fall to SDO
TD2
—
—
15
ns
Delay Time, CS Rise to SDO Tri-State
TD3
—
—
15
ns
Setup Time, CS to SCLK
TSU1
5
—
—
ns
Hold Time, SCLK Fall to CS
TH1
5
—
—
ns
Setup Time, SDI to SCLK Rise
TSU2
5
—
—
ns
Hold Time, SDI to SCLK Rise
TH2
5
—
—
ns
Delay Time Between Chip Selects (CS)
TCS
2
—
—
TC
TSU1
TD1
TC
SCLK
TH1
CS
TSU2
TH2
TCS
SDI
TD2
TD3
SDO
Figure 3. 4-Wire SPI Serial Interface Timing
Rev. 1.1
17
Si5347/46
Table 11. SPI Timing Specifications (3-Wire)
(VDD = 1.8 V ±5%, VDDA = 3.3 V ±5%, TA = –40 to 85 °C)
Parameter
Symbol
Min
Typ
Max
Units
SCLK Frequency
fSPI
—
—
20
MHz
SCLK Duty Cycle
TDC
40
—
60
%
SCLK Period
TC
50
—
—
ns
Delay Time, SCLK Fall to SDIO Turn-on
TD1
—
—
20
ns
Delay Time, SCLK Fall to SDIO Next-bit
TD2
—
—
15
ns
Delay Time, CS Rise to SDIO Tri-State
TD3
—
—
15
ns
Setup Time, CS to SCLK
TSU1
5
—
—
ns
Hold Time, SCLK Fall to CS
TH1
5
—
—
ns
Setup Time, SDI to SCLK Rise
TSU2
5
—
—
ns
Hold Time, SDI to SCLK Rise
TH2
5
—
—
ns
Delay Time Between Chip Selects (CS)
TCS
2
—
—
TC
TSU1
TC
SCLK
TH1
TD1
TD2
CS
TSU2
TH2
TCS
SDIO
TD3
Figure 4. 3-Wire SPI Serial Interface Timing
18
Rev. 1.1
Si5347/46
Table 12. Crystal Specifications
Parameter
Crystal Frequency Range
Symbol
Test Condition
Min
Typ
Max
Unit
fXTAL_48-54
Frequency range for
best jitter performance
48
—
54
MHz
Load Capacitance
CL_48-54
—
8
—
pF
Shunt Capacitance
CO_48-54
—
—
2
pF
Crystal Drive Level
dL_48-54
—
—
200
µW
Equivalent Series Resistance
Crystal Frequency Range
rESR_48-54 Refer to the Si5347/46 Family Reference Manual to determine ESR.
fXTAL_25
—
25
—
MHz
Load Capacitance
CL_25
—
8
—
pF
Shunt Capacitance
CO_25
—
—
3
pF
Crystal Drive Level
dL_25
—
—
200
µW
Equivalent Series Resistance
rESR_25
Refer to the Si5347/46 Family Reference Manual to determine ESR.
Notes:
1. The Si5347/46 is designed to work with crystals that meet the frequencies and specifications in Table 12.
2. Refer to the Si5347/46 Family Reference Manual for recommended 48 to 54 MHz crystals.
Rev. 1.1
19
Si5347/46
Table 13. Thermal Characteristics
Parameter
Symbol
Test Condition1
Value
Unit
JA
Still Air
22
°C/W
Air Flow 1 m/s
19.4
Air Flow 2 m/s
18.3
Si5347–64QFN
Thermal Resistance
Junction to Ambient
Thermal Resistance
Junction to Case
JC
9.5
Thermal Resistance
Junction to Board
JB
9.4
JB
9.3
JT
0.2
Thermal Resistance
Junction to Top Center
Si5346–44QFN
Thermal Resistance
Junction to Ambient
JA
Still Air
22.3
Air Flow 1 m/s
19.4
Air Flow 2 m/s
18.4
Thermal Resistance
Junction to Case
JC
10.9
Thermal Resistance
Junction to Board
JB
9.3
JB
9.2
JT
0.23
Thermal Resistance
Junction to Top Center
°C/W
Notes:
1. Based on PCB Dimension: 3” x 4.5”, PCB Thickness: 1.6 mm, PCB Land/Via under GNP pad: 36, Number of Cu
Layers: 4
20
Rev. 1.1
Si5347/46
Table 14. Absolute Maximum Ratings1,2,3
Parameter
DC Supply Voltage
Input Voltage Range
Latch-up Tolerance
Symbol
Test Condition
Value
Unit
VDD
–0.5 to 3.8
V
VDDA
–0.5 to 3.8
V
VDDO
–0.5 to 3.8
V
VDDS
–0.5 to 3.8
V
VI1
IN0 – IN3/FB_IN
–0.85 to 3.8
V
VI2
RST, OE0, OE1, I2C_SEL,
FINC, FDEC, PLL_SEL[1:0]
SDA/SDIO, A1/SDO, SCLK,
A0/CS
–0.5 to 3.8
V
VI3
XA/XB
–0.5 to 2.7
V
LU
ESD Tolerance
HBM
Junction Temperature
JESD78 Compliant
2.0
kV
TJCT
–55 to 150
°C
Storage Temperature Range
TSTG
–55 to +150
°C
Soldering Temperature
(Pb-free profile)3
TPEAK
260
°C
TP
20–40
s
Soldering Temperature Time at TPEAK
(Pb-free profile)4
100 pF, 1.5 k
Note:
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. 64-QFN and 44-QFN packages are RoHS-6 compliant.
3. For detailed MSL and packaging information, go to www.silabs.com/support/quality/pages/RoHSInformation.aspx.
4. The device is compliant with JEDEC J-STD-020.
Rev. 1.1
21
Si5347/46
3. Typical Operating Characteristics (Jitter and Phase Noise)
Figure 5. Input = 25 MHz; Output = 156.25 MHz, 2.5 V LVDS
Figure 6. Input = 25 MHz; Output = 625 MHz, 2.5 V LVDS
22
Rev. 1.1
Si5347/46
Figure 7. Input = 19.44 MHz; Output = 644.53125 MHz, 2.5 V LVDS
Figure 8. Input = 25 MHz; Output = 644.53125 MHz, 2.5 V LVDS
Rev. 1.1
23
Si5347/46
48-54MHz XTAL
or REFCLK
VDDA
VDD
VDDS
4. Detailed Block Diagram
3
XA
Si5347
XB
OSC
÷PXAXB
PD
LPF
Mn_A
Md_A
÷
DSPLL A
IN0
÷
IN0
P0n
P0d
PD
P
÷ 1n
P1d
IN1
IN1
IN2
÷
IN2
IN3
Mn_B
Md_B
÷
DSPLL B
P2n
P2d
PD
P
÷ 3n
P3d
IN3
LPF
LPF
Mn_C
Md_C
÷
DSPLL C
PD
÷R0
VDDO0
OUT0
OUT0
÷R1
VDDO1
OUT1
OUT1
÷R2
VDDO2
OUT2
OUT2
÷R3
VDDO3
OUT3
OUT3
÷R4
VDDO4
OUT4
OUT4
÷R5
VDDO5
OUT5
OUT5
÷R6
VDDO6
OUT6
OUT6
÷R7
VDDO7
OUT7
OUT7
LPF
÷
DSPLL D
Mn_D
Md_D
NVM
I2C_SEL
SDA/SDIO
A1/SDO
SCLK
SPI/
I2C
Status
Monitors
A0/CS
Figure 9. Si5347A/B Detailed Block Diagram
24
Rev. 1.1
OE1
OE0
DSPLL_SEL[1:0]
FINC
FDEC
INTR
LOS_XAXB
LOL_D
LOL_C
LOL_B
LOL_A
RST
2
VDDA
VDD
VDDS
Si5347/46
4
2
Si5346
48-54MHz XTAL
or REFCLK
XA
XB
OSC
÷PREF
P
÷ 0n
P0d
IN0
IN0
P
÷ 1n
P1d
IN1
IN1
P
÷ 2n
P2d
IN2
IN2
P
÷ 3n
P3d
IN3
IN3
PD
Mn_A
Md_A
DSPLL A
÷R1
VDDO1
OUT1
OUT1
÷R2
VDDO2
OUT2
OUT2
÷R3
VDDO3
OUT3
OUT3
LPF
Mn_B
÷
Md_B
DSPLL B
VDDO0
OUT0
OUT0
LPF
÷
PD
÷R0
I2C_SEL
SDA/SDIO
A1/SDO
SCLK
SPI/
I2C
NVM
Status
Monitors
OE1
OE0
INTR
LOS_XAXB
LOL_B
LOL_A
RST
A0/CS
Figure 10. Si5346 Detailed Block Diagram
Rev. 1.1
25
Si5347/46
5. Functional Description
The Si5347 takes advantage of Silicon Labs’ 4th generation DSPLL technology to offer the industry’s most
integrated and flexible jitter attenuating clock generator solution. Each of the DSPLLs operate independently from
each other and are controlled through a common serial interface. Each DSPLL has access to any of the four inputs
(IN0 to IN3) with manual or automatic input selection. Any of the output clocks (OUT0 to OUT7) can be configured
to any of the DSPLLs using a flexible crosspoint connection. The Si5346 is a smaller form factor dual DSPLL
version with four inputs and four outputs.
5.1. Frequency Configuration
The frequency configuration for each of the DSPLLs is programmable through the serial interface and can also be
stored in non-volatile memory. The combination of fractional input dividers (Pn/Pd), fractional frequency
multiplication (Mn/Md), and integer output division (Rn) allows each of the DSPLLs to lock to any input frequency
and generate virtually any output frequency. All divider values for a specific frequency plan are easily determined
using the ClockBuilder Pro utility.
5.2. DSPLL Loop Bandwidth
The DSPLL loop bandwidth determines the amount of input clock jitter attenuation. Register-configurable DSPLL
loop bandwidth settings in the range of 0.1 Hz to 4 kHz are available for selection for each of the DSPLLs. Since
the loop bandwidth is controlled digitally, each of the DSPLLs will always remain stable with less than 0.1 dB of
peaking regardless of the loop bandwidth selection.
5.2.1. Fastlock Feature
Selecting a low DSPLL loop bandwidth (e.g. 0.1 Hz) will generally lengthen the lock acquisition time. The fastlock
feature allows setting a temporary Fastlock Loop Bandwidth that is used during the lock acquisition process.
Higher fastlock loop bandwidth settings will enable the DSPLLs to lock faster. Fastlock Loop Bandwidth settings in
the range of 100 Hz to 4 kHz are available for selection. Once lock acquisition has completed, the DSPLL’s loop
bandwidth will automatically revert to the DSPLL Loop Bandwidth setting as described in section “5.2. DSPLL Loop
Bandwidth” . The fastlock feature can be enabled or disabled independently for each of the DSPLLs.
5.3. Modes of Operation
Once initialization is complete, each of the DSPLLs operates independently in one of three modes: Free-run Mode,
Lock Acquisition Mode, Locked Mode, or Holdover Mode. A state diagram showing the modes of operation is
shown in Figure 11. The following sections describe each of these modes in greater detail.
5.3.1. Initialization and Reset
Once power is applied, the device begins an initialization period where it downloads default register values and
configuration data from NVM and performs other initialization tasks. Communicating with the device through the
serial interface is possible once this initialization period is complete. No clocks will be generated until the
initialization is complete. There are two types of resets available. A hard reset is functionally similar to a device
power-up. All registers will be restored to the values stored in NVM, and all circuits will be restored to their initial
state including the serial interface. A hard reset is initiated using the RST pin or by asserting the hard reset bit. A
soft reset bypasses the NVM download. It is simply used to initiate register configuration changes. A hard reset
affects all DSPLLs, while a soft reset can either affect all or each DSPLL individually.
26
Rev. 1.1
Si5347/46
Power-Up
Reset and
Initialization
No valid
input clocks
selected
Free-run
Valid input clock
selected
An input is qualified
and available for
selection
Phase lock on
selected input
clock is achieved
Holdover
Mode
No
Ye
Is holdover
history valid?
Lock Acquisition
(Fast Lock)
s
Selected input
clock fails
Locked
Mode
Figure 11. Modes of Operation
5.3.2. Free-run Mode
Once power is applied to the Si5347 and initialization is complete, all four DSPLLs will automatically enter Free-run
Mode. The frequency accuracy of the generated output clocks in Free-run Mode is entirely dependent on the
frequency accuracy of the external crystal or reference clock on the XA/XB pins. For example, if the crystal
frequency is ±100 ppm, then all the output clocks will be generated at their configured frequency ±100 ppm in Freerun Mode. Any drift of the crystal frequency will be tracked at the output clock frequencies. A TCXO or OCXO is
recommended for applications that need better frequency accuracy and stability while in Free-run Mode or
Holdover Mode.
5.3.3. Lock Acquisition Mode
Each of the DSPLLs independently monitors its configured inputs for a valid clock. If at least one valid clock is
available for synchronization, a DSPLL will automatically start the lock acquisition process.
If the fast lock feature is enabled, a DSPLL will acquire lock using the Fastlock Loop Bandwidth setting and then
transition to the DSPLL Loop Bandwidth setting when lock acquisition is complete. During lock acquisition the
outputs will generate a clock that follows the VCO frequency change as it pulls-in to the input clock frequency.
5.3.4. Locked Mode
Once locked, a DSPLL will generate output clocks that are both frequency and phase locked to their selected input
clocks. At this point, any XTAL frequency drift will not affect the output frequency. Each DSPLL has its own LOL pin
and status bit to indicate when lock is achieved. See "5.7.4. LOL Detection" on page 35 for more details on the
operation of the loss of lock circuit.
Rev. 1.1
27
Si5347/46
5.3.5. Holdover Mode
Any of the DSPLLs will automatically enter Holdover Mode when the selected input clock becomes invalid and no
other valid input clocks are available for selection. Each DSPLL uses an averaged input clock frequency as its final
holdover frequency to minimize the disturbance of the output clock phase and frequency when an input clock
suddenly fails. The holdover circuit for each DSPLL stores up to 120 seconds of historical frequency data while
locked to a valid clock input. The final averaged holdover frequency value is calculated from a programmable
window within the stored historical frequency data. Both the window size and delay are programmable as shown in
Figure 12. The window size determines the amount of holdover frequency averaging. The delay value allows
ignoring frequency data that may be corrupt just before the input clock failure.
Clock Failure and
Entry into Holdover
Historical Frequency Data Collected
time
120s
Programmable historical data window
used to determine the final holdover value
Programmable delay
30ms, 60ms, 1s,10s, 30s, 60s
0s
1s,10s, 30s, 60s
Figure 12. Programmable Holdover Window
When entering Holdover Mode, a DSPLL will pull its output clock frequency to the calculated averaged holdover
frequency. While in Holdover Mode, the output frequency drift is entirely dependent on the external crystal or
external reference clock connected to the XA/XB pins. If the clock input becomes valid, a DSPLL will automatically
exit the Holdover Mode and reacquire lock to the new input clock. This process involves pulling the output clock
frequencies to achieve frequency and phase lock with the input clock. This pull-in process is glitchless, and its rate
is controlled by the DSPLL bandwidth or the fastlock bandwidth. These options are register programmable.
5.4. Digitally-Controlled Oscillator (DCO) Mode
The DSPLLs support a DCO mode where their output frequencies are adjustable in predefined steps defined by
frequency step words (FSW).The frequency adjustments are controlled through the serial interface or by pin control
using frequency increment (FINC) or decrement (FDEC). A FINC will add the frequency step word to the DSPLL
output frequency, while a FDEC will decrement it. The DCO mode is available when the DSPLL is operating in
either Free-run or Locked Mode.
28
Rev. 1.1
Si5347/46
5.5. External Reference (XA/XB)
An external crystal (XTAL) is used in combination with the internal oscillator (OSC) to produce an ultra-low jitter
reference clock for the DSPLLs and for providing a stable reference for the Free-run and Holdover Modes. A
simplified diagram is shown in Figure 13. The device includes internal XTAL loading capacitors, which eliminates
the need for external capacitors and also has the benefit of reduced noise coupling from external sources. Refer to
Table 12 for crystal specifications. A crystal in the range of 48 MHz to 54 MHz is recommended for best jitter
performance. Frequency offsets due to CL mismatch can be adjusted using the frequency adjustment feature,
which allows frequency adjustments of ±200 ppm. The Si5347/46 Family Reference Manual provides additional
information on PCB layout recommendations for the crystal to ensure optimum jitter performance.
The device can also accommodate an external reference clock (REFCLK) instead of a crystal. Selection between
the external XTAL or REFCLK is controlled by register configuration. The internal crystal loading capacitors (CL)
are disabled in this mode. Refer to Table 3 for REFCLK requirements when using this mode. The Si5347/46 Family
Reference Manual provides additional information on PCB layout recommendations for the crystal to ensure
optimum jitter performance. A PREF divider is available to accommodate external clock frequencies higher than
54 MHz. Although the REFCLK frequency range of 25 MHz to 200 MHz is supported, frequencies in the range of
48 MHz to 54 MHz will achieve the best output jitter performance.
48-54MHz
XO
48-54MHz
XO
48-54MHz
XTAL
XA
100
XB
2xCL
XA
2xCL
OSC
XA
XB
2xCL
2xCL
Si5347/46
Crystal Resonator Connection
2xCL
2xCL
OSC
OSC
÷PREF
XB
÷PREF
÷PREF
Si5347/46
Si5347/46
Differential XO Connection
Single-Ended XO Connection
Figure 13. Crystal Resonator and External Reference Clock Connection Options
Rev. 1.1
29
Si5347/46
5.6. Inputs (IN0, IN1, IN2, IN3)
There are four inputs that can be used to synchronize any of the DSPLLs. The inputs accept both differential and
single-ended clocks. A crosspoint between the inputs and the DSPLLs allows any of the inputs to connect to any of
the DSPLLs as shown in Figure 14.
Si5347
Input
Crosspoint
IN0
IN0
IN1
IN1
IN2
IN2
IN3
IN3
÷
P0n
P0d
÷
P1n
P1d
P
÷ 2n
P2d
P
÷ 3n
P3d
0
1
2
3
DSPLL
A
0
1
2
3
DSPLL
B
0
1
2
3
DSPLL
C
0
1
2
3
DSPLL
D
Figure 14. DSPLL Input Selection Crosspoint
5.6.1. Input Selection
Input selection for each of the DSPLLs can be made manually through register control or automatically using an
internal state machine.
5.6.2. Manual Input Selection
In Manual Mode, the input selection is made by writing to a register. If there is no clock signal on the selected input,
the DSPLL will automatically enter Holdover Mode.
5.6.3. Automatic Input Selection
When configured in this mode, the DSPLL automatically selects a valid input that has the highest configured
priority. The priority scheme is independently configurable for each DSPLL and supports revertive or non-revertive
selection.
All inputs are continuously monitored for loss of signal (LOS) and/or invalid frequency range (OOF). Only inputs
that do not assert both the LOS and OOF monitors can be selected for synchronization by the automatic state
machine. The DSPLL(s) will enter the Holdover mode if there are no valid inputs available.
5.6.4. Input Configuration and Terminations
Each of the inputs can be configured as differential or single-ended LVCMOS. The recommended input termination
schemes are shown in Figure 15. Standard 50% duty cycle signals must be ac-coupled, while low duty cycle
Pulsed CMOS signals can be dc-coupled. Unused inputs can be disabled and left unconnected when not in use.
30
Rev. 1.1
Si5347/46
Standard AC‐coupled Differential LVDS
Si5347/46
50
INx
Standard
100
3.3 V, 2.5 V LVDS or CML
INx
50
Pulsed CMOS
Standard AC‐coupled Differential LVPECL
50
INx
Si5347/46
Standard
100
INx
50
3.3 V, 2.5 V LVPECL
Pulsed CMOS
Standard AC‐coupled Single‐ended
50
INx
3.3 V, 2.5 V, 1.8 V
LVCMOS
Si5347/46
Standard
INx
Pulsed CMOS
Pulsed CMOS DC‐coupled Single‐ended
Si5347/46
R1
INx
50
R2
3.3 V, 2.5 V, 1.8 V LVCMOS
Resistor values for fIN_PULSED < 1 MHz
VDD
1.8V
2.5V
3.3V
R1 ()
549
680
750
R2 ()
442
324
243
Standard
INx
Pulsed CMOS
Figure 15. Termination of Differential and LVCMOS Input Signals
5.6.5. Hitless Input Switching
Hitless switching is a feature that prevents a phase transient from propagating to the output when switching
between two clock inputs that have a fixed phase relationship. A hitless switch can only occur when the two input
frequencies are frequency locked, meaning that they have to be exactly at the same frequency, or at a fractional
frequency relationship to each other. When hitless switching is enabled, the DSPLL simply absorbs the phase
difference between the two input clocks during an input switch. When disabled, the phase difference between the
two inputs is propagated to the output at a rate determined by the DSPLL Loop Bandwidth. The hitless switching
feature supports clock frequencies down to the minimum input frequency of 8 kHz. Hitless switching can be
enabled on a per DSPLL basis.
5.6.6. Glitchless Input Switching
The DSPLLs have the ability of switching between two input clock frequencies that are up to ±500 ppm apart. The
DSPLL will pull-in to the new frequency using the DSPLL Loop Bandwidth or using the Fastlock Loop Bandwidth if
it is enabled. The loss of lock (LOL) indicator will assert while the DSPLL is pulling-in to the new clock frequency.
There will be no output runt pulses generated at the output during the transition.
Rev. 1.1
31
Si5347/46
5.6.7. Synchronizing to Gapped Input Clocks
Each of the DSPLLs support locking to an input clock that has missing periods. This is also referred to as a gapped
clock. The purpose of gapped clocking is to modulate the frequency of a periodic clock by selectively removing
some of its cycles. Gapping a clock severely increases its jitter, so a phase-locked loop with high jitter tolerance
and low loop bandwidth is required to produce a low-jitter periodic clock. The resulting output will be a periodic nongapped clock with an average frequency of the input with its missing cycles. For example, an input clock of
100 MHz with one cycle removed every 10 cycles will result in a 90 MHz periodic non-gapped output clock. This is
shown in Figure 16.
Gapped Input Clock
Periodic Output Clock
100 MHz clock
1 missing period every 10
90 MHz non-gapped clock
100 ns
100 ns
DSPLL
1
10 ns
2
3
4
5
6
7
8
9
1
10
Period Removed
2
3
4
5
6
7
8
9
11.11111... ns
Figure 16. Generating an Averaged Clock Output Frequency from a Gapped Clock Input
A valid gapped clock input must have a minimum frequency of 10 MHz with a maximum of two missing cycles out
of every 8. Locking to a gapped clock will not trigger the LOS, OOF, and LOL fault monitors. Clock switching
between gapped clocks may violate the hitless switching specification in Table 8 when the switch occurs during a
gap in either input clock.
32
Rev. 1.1
Si5347/46
5.7. Fault Monitoring
All four input clocks (IN0, IN1, IN2, IN3) are monitored for LOS and OOF as shown in Figure 17. The reference at
the XA/XB pins is also monitored for LOS since it provides a critical reference clock for the DSPLLs. Each of the
DSPLLs also has an LOL indicator, which is asserted when synchronization is lost with their selected input clock.
XA XB
Si5347
OSC
LOS
DSPLL A
LOL
PD
LPF
÷M
IN0
IN0
IN1
IN1
IN2
P
÷ 0n
P0d
LOS
P1n
P1d
LOS
÷
P2n
P2d
LOS
OOF
Precision
Fast
÷
P3n
P3d
LOS
OOF
Precision
Fast
÷
IN2
Precision
OOF
Fast
OOF
DSPLL B
LOL
PD
Precision
Fast
LPF
÷M
DSPLL C
LOL
PD
IN3
IN3
LPF
÷M
DSPLL D
LOL
PD
LPF
÷M
Figure 17. Si5347 Fault Monitors
5.7.1. Input LOS Detection
The loss of signal monitor measures the period of each input clock cycle to detect phase irregularities or missing
clock edges. Each of the input LOS circuits has its own programmable sensitivity which allows ignoring missing
edges or intermittent errors. Loss of signal sensitivity is configurable using the ClockBuilder Pro utility. The LOS
status for each of the monitors is accessible by reading a status register. The live LOS register always displays the
current LOS state and a sticky register always stays asserted until cleared. An option to disable any of the LOS
monitors is also available.
Monitor
Sticky
LOS
LOS
LOS
en
Live
Figure 18. LOS Status Indicators
Rev. 1.1
33
Si5347/46
5.7.2. XA/XB LOS Detection
A LOS monitor is available to ensure that the external crystal or reference clock is valid. By default the output
clocks are disabled when XAXB_LOS is detected. This feature can be disabled such that the device will continue to
produce output clocks when XAXB_LOS is detected.
5.7.3. OOF Detection
Each input clock is monitored for frequency accuracy with respect to an OOF reference, which it considers as its
“0_ppm” reference.
This OOF reference can be selected as either:
XA/XB
pins
Any input clock (IN0, IN1, IN2, IN3)
The final OOF status is determined by the combination of both a precise OOF monitor and a fast OOF monitor as
shown in Figure 19. An option to disable either monitor is also available. The live OOF register always displays the
current OOF state and its sticky register bit stays asserted until cleared.
Monitor
Sticky
en
Precision
OOF
LOS
OOF
Fast
Live
en
Figure 19. OOF Status Indicator
5.7.3.1. Precision OOF Monitor
The precision OOF monitor circuit measures the frequency of all input clocks to within ±1 ppm accuracy with
respect to the selected OOF frequency reference. A valid input clock frequency is one that remains within the OOF
frequency range, which is register configurable from ±2 ppm to ±500 ppm in steps of 2 ppm. A configurable amount
of hysteresis is also available to prevent the OOF status from toggling at the failure boundary. An example is shown
in Figure 20. In this case, the OOF monitor is configured with a valid frequency range of ±6 ppm and with 2 ppm of
hysteresis. An option to use one of the input pins (IN0 – IN3) as the 0 ppm OOF reference instead of the XA/XB
pins is available. This option is register-configurable.
OOF Declared
fIN
Hysteresis
Hysteresis
OOF Cleared
-6 ppm
(Set)
-4 ppm
(Clear)
0 ppm
OOF
Reference
+4 ppm
(Clear)
+6 ppm
(Set)
Figure 20. Example of Precise OOF Monitor Assertion and De-assertion Triggers
5.7.3.2. Fast OOF Monitor
Because the precision OOF monitor needs to provide 1 ppm of frequency measurement accuracy, it must measure
the monitored input clock frequencies over a relatively long period of time. This may be too slow to detect an input
clock that is quickly ramping in frequency. An additional level of OOF monitoring called the Fast OOF monitor runs
in parallel with the precision OOF monitors to quickly detect a ramping input frequency. The Fast OOF monitor
asserts OOF on an input clock frequency that has changed by greater than ±4000 ppm.
34
Rev. 1.1
Si5347/46
5.7.4. LOL Detection
There is an LOL monitor for each of the DSPLLs. The LOL monitor asserts an LOL register bit when a DSPLL has
lost synchronization with its selected input clock. There is also a dedicated loss of lock pin that reflects the loss of
lock condition for each of the DSPLLs (LOL_A, LOL_B, LOL_C, LOL_D). The LOL monitor functions by measuring
the frequency difference between the input and feedback clocks at the phase detector. There are two LOL
frequency monitors, one that sets the LOL indicator (LOL Set) and another that clears the indicator (LOL Clear). An
optional timer is available to delay clearing of the LOL indicator to allow additional time for the DSPLL to completely
lock to the input clock. The timer is also useful to prevent the LOL indicator from toggling or chattering as the
DSPLL completes lock acquisition. A block diagram of the LOL monitor is shown in Figure 21. The live LOL register
always displays the current LOL state and a sticky register always stays asserted until cleared. The LOL pin
reflects the current state of the LOL monitor.
Si5347
Sticky
LOS
LOL Status Registers
Live
DSPLL D
DSPLL C
DSPLL B
DSPLL A
LOL_D
LOL Monitor
LOL_C
LOL
Clear
t
LOL_B
LOL_A
LOL
Set
DSPLL A
fIN
PD
LPF
÷M
Figure 21. LOL Status Indicators
Each of the LOL frequency monitors has adjustable sensitivity, which is register-configurable from 0.1 ppm to
10000 ppm. Having two separate frequency monitors allows for hysteresis to help prevent chattering of LOL status.
An example configuration where LOCK is indicated when there is less than 0.2 ppm frequency difference at the
inputs of the phase detector and LOL is indicated when there is more than 2 ppm frequency difference is shown in
Figure 22.
Clear LOL
Threshold
Set LOL
Threshold
Lock Acquisition
LOL
Hysteresis
Lost Lock
LOCKED
0
0.2
2
20,000
Phase Detector Frequency Difference (ppm)
Figure 22. LOL Set and Clear Thresholds
Rev. 1.1
35
Si5347/46
An optional timer is available to delay clearing of the LOL indicator to allow additional time for the DSPLL to
completely lock to the input clock. The timer is also useful to prevent the LOL indicator from toggling or chattering
as the DSPLL completes lock acquisition. The configurable delay value depends on frequency configuration and
loop bandwidth of the DSPLL and is automatically calculated using the ClockBuilderPro utility.
5.7.5. Interrupt Pin (INTR)
An interrupt pin (INTR) indicates a change in state with any of the status indicators for any of the DSPLLs. All
status indicators are maskable to prevent assertion of the interrupt pin. The state of the INTR pin is reset by
clearing the sticky status registers.
mask
IN0_LOS_STKY
mask
IN0
IN0_OOF_STKY
mask
IN1_LOS_STKY
mask
IN1
IN1_OOF_STKY
mask
IN2_LOS_STKY
mask
IN2
IN2_OOF_STKY
INTR
mask
IN3_LOS_STKY
mask
IN3
IN3_OOF_STKY
mask
XAXB_LOS_STKY
mask
LOLA_STKY
mask
LOLB_STKY
mask
LOL
LOLC_STKY
mask
LOLD_STKY
mask
HOLDA_STKY
mask
HOLDB_STKY
mask
HOLD
HOLDC_STKY
mask
HOLDD_STKY
Figure 23. Interrupt Triggers and Masks
36
Rev. 1.1
Si5347/46
5.8. Outputs
The Si5347 supports up to eight differential output drivers and the Si5346 supports four. Each driver has a
configurable voltage amplitude and common mode voltage covering a wide variety of differential signal formats
including LVPECL, LVDS, HCSL, and CML. In addition to supporting differential signals, any of the outputs can be
configured as single-ended LVCMOS (3.3 V, 2.5 V, or 1.8 V) providing up to 16 single-ended outputs, or any
combination of differential and single-ended outputs.
5.8.1. Output Crosspoint
A crosspoint allows any of the output drivers to connect with any of the DSPLLs as shown in Figure 24. The
crosspoint configuration is programmable and can be stored in NVM so that the desired output configuration is
ready at power-up.
Si5347A/B
Output
Crosspoint
A
B
C
D
DSPLL
A
DSPLL
B
DSPLL
C
DSPLL
D
÷R0
VDDO0
OUT0
OUT0
A
B
C
D
÷R1
VDDO1
OUT1
OUT1
A
B
C
D
÷R2
VDDO2
OUT2
OUT2
A
B
C
D
÷R3
VDDO3
OUT3
OUT3
A
B
C
D
÷R4
VDDO4
OUT4
OUT4
A
B
C
D
÷R5
VDDO5
OUT5
OUT5
A
B
C
D
÷R6
VDDO6
OUT6
OUT6
A
B
C
D
÷R7
VDDO7
OUT7
OUT7
Figure 24. Si5347A/B DSPLL to Output Driver Crosspoint
Rev. 1.1
37
Si5347/46
5.8.2. Differential Output Terminations
Note: In this document, the terms, LVDS and LVPECL, refer to driver formats that are compatible with these signaling
standards.
The differential output drivers support both ac-coupled and dc-coupled terminations as shown in Figure 25.
AC-coupled LVDS/LVPECL
DC-coupled LVDS
VDDO = 3.3V, 2.5V, 1.8V
VDDO = 3.3V, 2.5V, 1.8V
50
OUTx
OUTx
100
OUTx
100
OUTx
50
50
50
AC-coupled LVPECL
DC-coupled LVCMOS
3.3V, 2.5V, 1.8V
LVCMOS
VDDO = 3.3V, 2.5V, 1.8V
VDD – 1.3V
VDDO = 3.3V, 2.5V
50
50
Rs
OUTx
OUTx
OUTx
50
OUTx
50
50
Si5347/46
Si5347/46
Rs
AC-coupled HCSL
VDDRX
VDDO = 3.3V, 2.5V, 1.8V
R1
OUTx
R1
50
OUTx
Standard
HCSL
Receiver
50
Si5347/46
R2
R2
For VCM = 0.35V
VDDRX
R1
R2
3.3V
442 
56.2 
2.5V
332 
59 
1.8V
243 
63.4 
Figure 25. Supported Differential Output Terminations
38
Internally
self-biased
Si5347/46
Si5347/46
Rev. 1.1
50
Si5347/46
5.8.3. LVCMOS Output Terminations
LVCMOS outputs are dc-coupled as shown in Figure 26.
3.3 V, 2.5 V, 1.8 V
LVCMOS
VDDO = 3.3 V, 2.5 V, 1.8 V
50
OUTx
Rs
OUTx
50
Si5347/46
Rs
Figure 26. LVCMOS Output Terminations
5.8.4. Output Signal Format
The differential output amplitude and common mode voltage are both fully programmable and compatible with a
wide variety of signal formats, including LVDS and LVPECL. In addition to supporting differential signals, any of the
outputs can be configured as LVCMOS (3.3 V, 2.5 V, or 1.8 V) drivers providing up to 20 single-ended outputs or
any combination of differential and single-ended outputs.
5.8.5. Differential Output Amplitude Modes
There are two selectable differential output amplitude modes: normal and low power. Each output can support a
unique mode.
Differential
Normal Mode: When an output driver is configured in normal amplitude mode, its output
amplitude is selectable as one of 8 settings ranging from 130 mVpp_se to 920 mVpp_se in increments of
100 mV. The output impedance in the normal mode is 100 differentialAny of the ac-coupled
terminations shown in Figure 25 are supported in this mode.
Differential Low Power Mode: When an output driver is configured in low power mode, its output
amplitude is configurable as one of 8 settings ranging from 200 mVpp_se to 1600 mVpp_se in increments
of 200 mV. The output driver is in high impedance mode and supports standard 50 PCB traces. Any of
the ac-coupling terminations shown in Figure 25 are supported in this mode.
5.8.6. Programmable Common Mode Voltage For Differential Outputs
The common mode voltage (VCM) for the differential normal and low power modes is programmable in 100 mV
increments from 0.7 V to 2.3 V depending on the voltage available at the output’s VDDO pin. Setting the common
mode voltage is useful when dc-coupling the output drivers.
5.8.7. LVCMOS Output Impedance Selection
Each LVCMOS driver has a configurable output impedance to accommodate different trace impedances and drive
strengths. A source termination resistor is recommended to help match the selected output impedance to the trace
impedance. There are three programmable output impedance selections for each VDDO options as shown in
Table 15. Note that selecting a lower source impedance may result in higher output power consumption.
Table 15. Typical Output Impedance (ZS)
CMOS_DRIVE_Selection
VDDO
OUTx_CMOS_DRV=1
OUTx_CMOS_DRV=2
OUTx_CMOS_DRV=3
3.3 V
38 
30 
22 
2.5 V
43 
35 
24 
1.8 V
—
46 
31 
Rev. 1.1
39
Si5347/46
5.8.8. LVCMOS Output Signal Swing
The signal swing (VOL/VOH) of the LVCMOS output drivers is set by the voltage on the VDDO pins. Each output
driver has its own VDDO pin allowing a unique output voltage swing for each of the LVCMOS drivers. Each output
driver automatically detects the voltage on the VDDO pin to properly determine the correct output voltage.
5.8.9. LVCMOS Output Polarity
When a driver is configured as an LVCMOS output, it generates a clock signal on both pins (OUTx and OUTx). By
default the clock on the OUTx pin is generated with the same polarity (in phase) with the clock on the OUTx pin.
The polarity of these clocks is configurable, which enables complementary clock generation and/or inverted
polarity with respect to other output drivers.
5.8.10. Output Enable/Disable
The Si5347/46 allows enabling/disabling outputs by pin or register control, or a combination of both. Two output
enable pins are available (OE0, OE1). The output enable pins can be mapped to any of the outputs (OUTx)
through register configuration. By default OE0 controls all of the outputs while OE1 remains unmapped and has no
effect until configured. Figure 27 shows an example of an output enable mapping scheme that is register
configurable and can be stored in NVM as the default at power-up.
Enabling and disabling outputs can also be controlled by register control. This allows disabling one or more output
when the OE pin(s) has them enabled. By default the output enable register settings are configured to allow the OE
pins to have full control.
Si5346
Output
Crosspoint
DSPLL
A
Si5346
Output
Crosspoint
DSPLL
A
OUT0
A
B
÷R0
A
B
÷R1
OUT1
A
B
÷R2
OUT2
OUT0
OUT1
A
B
÷R0
A
B
÷R1
OUT0
OUT0
OUT1
OUT1
OE0
DSPLL
B
A
B
÷R3
OUT2
DSPLL
B
OUT3
A
B
÷R2
OUT2
A
B
÷R3
OUT3
OUT2
OUT3
OUT3
OE0
OE1
OE1
An example of a configurable output enable
scheme. In this case OE0 controls the outputs
associated with DSPLL A, while OE1 controls
the outputs of DSPLL B.
In its default state the OE0 pin enables/
disables all outputs. The OE1 pin is not
mapped and has no effect on outputs.
Figure 27. Example of Configuring Output Enable Pins
5.8.11. Output Disable During LOL
By default a DSPLL that is out of lock will generate either free-running clocks or generate clocks in holdover mode.
There is an option to disable the outputs when a DSPLL is LOL. This option can be useful to force a downstream
PLL into holdover.
40
Rev. 1.1
Si5347/46
5.8.12. Output Disable During XAXB_LOS
The internal oscillator circuit (OSC) in combination with the external crystal (XTAL) provides a critical function for
the operation of the DSPLLs. In the event of a crystal failure the device will assert an XAXB_LOS alarm. By default
all outputs will be disabled during assertion of the XAXB_LOS alarm. There is an option to leave the outputs
enabled during an XAXB_LOS alarm, but the frequency accuracy and stability will be indeterminate during this fault
condition.
5.8.13. Output Driver State When Disabled
The disabled state of an output driver is register configurable as disable low, disable high, or disable highimpedance.
5.8.14. Synchronous/Asynchronous Output Disable
Outputs can be configured to disable synchronously or asynchronously. In synchronous disable mode the output
will wait until a clock period has completed before the driver is disabled. This prevents unwanted runt pulses from
occurring when disabling an output. In asynchronous disable mode, the output clock will disable immediately
without waiting for the period to complete.
5.8.15. Output Divider (R) Synchronization
All the output R dividers are reset to a known state during the power-up initialization period. This ensures
consistent and repeatable phase alignment across all output drivers. Resetting the device using the RST pin or
asserting the hard reset bit will have the same result.
5.9. Power Management
Unused inputs, output drivers, and DSPLLs can be powered down when unused. Consult the Si5347/46 Family
Reference Manual and ClockBuilder Pro configuration utility for details.
5.10. In-Circuit Programming
The Si5347/46 is fully configurable using the serial interface (I2C or SPI). At power-up the device downloads its
default register values from internal non-volatile memory (NVM). Application specific default configurations can be
written into NVM allowing the device to generate specific clock frequencies at power-up. Writing default values to
NVM is in-circuit programmable with normal operating power supply voltages applied to its VDD and VDDA pins. The
NVM is two time writable. Once a new configuration has been written to NVM, the old configuration is no longer
accessible. Refer to the Si5347/46 Family Reference Manual for a detailed procedure for writing registers to NVM.
5.11. Serial Interface
Configuration and operation of the Si5347/46 is controlled by reading and writing registers using the I2C or SPI
interface. The I2C_SEL pin selects I2C or SPI operation. Communication with both 3.3 V and 1.8 V host is
supported. The SPI mode operates in either 4-wire or 3-wire mode. See the Si5347/46 Family Reference Manual
for details.
5.12. Custom Factory Preprogrammed Parts
For applications where a serial interface is not available for programming the device, custom pre-programmed
parts can be ordered with a specific configuration written into NVM. A factory pre-programmed part will generate
clocks at power-up. Custom, factory-preprogrammed devices are available. Use the ClockBuilder Pro custom part
number wizard (www.silabs.com/clockbuilderpro) to quickly and easily request and generate a custom part number
for your configuration.
In less than three minutes, you will be able to generate a custom part number with a detailed data sheet addendum
matching your design’s configuration. Once you receive the confirmation email with the data sheet addendum,
simply place an order with your local Silicon Labs sales representative. Samples of your pre-programmed device
will typically ship in about two weeks.
Rev. 1.1
41
Si5347/46
5.13. How to Enable Features and/or Configuration Settings Not Available in
ClockBuilder Pro for Factory Pre-programmed Devices
As with essentially all modern software utilities, ClockBuilder Pro is continuously updated and enhanced. By
registering at www.silabs.com, you will be notified whenever changes are made and what the impact of those
changes are. This update process will ultimately enable ClockBuilder Pro users to access all features and register
setting values documented in this data sheet and the Si347/46 Family Reference Manual.
However, if you must enable or access a feature or register setting value so that the device starts up with this
feature or a register setting, but the feature or register setting is not yet available in CBPro, you must contact a
Silicon Labs applications engineer for assistance. One example of this type of feature or custom setting is the
customizable output amplitude and common voltages for the clock outputs. After careful review of your project file
and requirements, the Silicon Labs applications engineer will email back your CBPro project file with your specific
features and register settings enabled using what is referred to as the manual "settings override" feature of CBPro.
"Override" settings to match your request(s) will be listed in your design report file. Examples of setting "overrides"
in a CBPro design report are shown in Table 16.
Table 16. Setting Overrides
Location
Customer Name
Engineering Name
Type
Target
Dec Value Hex Value
0x0535[0]
FORCE_HOLD_PLLB
OLA_HO_FORCE
No NVM
N/A
1
0x1
0x0B48[4:0]
OOF_DIV_CLK_DIS
OOF_DIV_CLK_DIS
User
OPN&EVB
31
0x1F
Once you receive the updated design file, simply open it in CBPro. The device will begin operation after startup
with the values in the NVM file. The flowchart for this process is shown in Figure 28.
42
Rev. 1.1
Si5347/46
End: Place sample order
Start
Do I need a pre‐programmed device with a feature or setting which is unavailable in ClockBuilder Pro?
No
Configure device using CBPro
Generate Custom OPN in CBPro
Yes
Contact Silicon Labs Technical Support
to submit & review your non‐standard configuration request & CBPro project file
Receive updated CBPro project file from
Silicon Labs with “Settings Override”
Yes
Load project file
into CBPro and test
Does the updated CBPro Project file match your
requirements?
Figure 28. Process for Requesting Non-Standard CBPro Features
Rev. 1.1
43
Si5347/46
6. Register Map
The register map is divided into multiple pages where each page has 256 addressable registers. Page 0 contains
frequently accessed registers, such as alarm status, resets, device identification, etc. Other pages contain registers
that need less frequent access such as frequency configuration and general device settings. Refer to the Si534746 Family Reference Manual for a complete list of register descriptions and settings.
44
Rev. 1.1
Si5347/46
7. Pin Descriptions
Si5347A/B 64QFN
Top View
VDD
OE1
OUT3
OUT3
VDDO3
37
35
34
IN3
VDD
41
I2C_SEL
IN3
42
38
IN0
43
39
IN0
44
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
IN0
IN0
IN3
IN3
VDD
OUT7
OUT7
VDDO7
RSVD
RSVD
OUT6
OUT6
VDDO6
OUT5
OUT5
VDDO5
Si5346 44QFN
Top View
48
FINC
2
47
LOL_D
LOL_A
3
46
VDD
IN1
1
33
LOS_XAXB
LOL_B
LOL_C
4
45
OUT4
IN1
2
32
5
44
OUT4
RST
3
31
VDD
OUT2
RST
X1
6
43
VDDO4
X1
4
30
OUT2
7
42
FDEC
5
29
VDDO2
XA
8
41
OE1
XA
XB
XB
9
40
VDDS
X2
VDDA
7
VDDA
GND
Pad
36
1
IN1
40
IN1
GND
Pad
28
LOL_A
27
LOL_B
8
26
VDDS
9
25
OUT1
6
17
18
19
20
21
22
INTR
VDDO0
OUT0
OUT0
VDD
NC
16
32
A1/SDO
SDA/SDIO
A0/CS
RSVD
RSVD
VDDO0
OUT0
OUT0
LOS_XAXB
DSPLL_SEL0
DSPLL_SEL1
NC
VDDO1
OUT1
OUT1
VDD
A0/CS
VDDO2
15
OUT2
33
A1/SDO
34
14
IN2 15
SCLK 16
SCLK
OUT2
13
35
12
VDDO1
IN2 14
OE0
SDA/SDIO
23
31
11
30
IN2
29
VDDO3
28
36
27
OUT1
VDDA 13
26
24
25
10
24
IN2
23
OUT3
22
37
21
INTR 12
20
I2C_SEL
OUT3
19
38
18
39
17
X2 10
OE0 11
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
IN0
IN0
IN3
IN3
VDD
RSVD
RSVD
RSVD
RSVD
RSVD
RSVD
RSVD
RSVD
OUT3
OUT3
VDDO3
Si5347C/D 64QFN
Top View
IN1
1
48
FINC
IN1
2
47
LOL_D
LOL_A
3
46
VDD
LOL_B
LOL_C
4
45
OUT2
5
44
OUT2
RST
X1
6
43
VDDO2
7
42
FDEC
XA
8
41
OE1
XB
9
40
VDDS
X2
10
39
I2C_SEL
OE0
11
38
OUT1
GND
Pad
32
31
RSVD
RSVD
RSVD
VDD
A1/SDO
SDA/SDIO
A0/CS
RSVD
RSVD
VDDO0
OUT0
OUT0
LOS_XAXB
DSPLL_SEL0
DSPLL_SEL1
NC
Rev. 1.1
30
RSVD
29
33
28
16
27
RSVD
SCLK
26
34
25
15
24
RSVD
IN2
23
35
22
14
21
VDDO1
IN2
20
OUT1
36
19
37
13
18
12
17
INTR
VDDA
45
Si5347/46
Table 17. Si5347/46 Pin Descriptions1
Pin
Name
Pin Number
Si5347A/B Si5347C/D
Si5346
Pin
Type2
Function
Inputs
XA
8
8
5
I
XB
9
9
6
I
X1
7
7
4
I
X2
10
10
7
I
IN0
63
63
43
I
IN0
64
64
44
I
IN1
1
1
1
I
IN1
2
2
2
I
IN2
14
14
10
I
IN2
15
15
11
I
IN3
61
61
41
I
IN3
62
62
42
I
Crystal Input. Input pin for external crystal (XTAL). Alternatively
these pins can be driven with an external reference clock (REFCLK). An internal register bit selects XTAL or REFCLK mode.
Default is XTAL mode.
XTAL Ground. Connect these pins directly to the XTAL ground
pins. X1, X2, and the XTAL ground pins should be separated from
the PCB ground plane. Refer to the Si5347/46 Family Reference
Manual for layout guidelines. These pins should be left disconnected when connecting XA/XB pins to an external reference clock
(REFCLK).
Clock Inputs. These pins accept an input clock for synchronizing
the device. They support both differential and single-ended clock
signals. Refer to “5.6.4. Input Configuration and Terminations” for
input termination options. These pins are high-impedance and must
be terminated externally. The negative side of the differential input
must be grounded when accepting a single-ended clock.
Notes:
1. Refer to the Si5347/46 Family Reference Manual for more information on register setting names.
2. I = Input, O = Output, P = Power.
3. The IO_VDD_SEL control bit (0x0943 bit 0) selects 3.3 V or 1.8 V operation.
4. The voltage on the VDDS pin(s) determines 3.3 V or 1.8 V operation.
46
Rev. 1.1
Si5347/46
Table 17. Si5347/46 Pin Descriptions1 (Continued)
Pin
Name
Pin Number
Si5347A/B Si5347C/D
Si5346
Pin
Type2
Function
Outputs
OUT0
24
24
20
O
OUT0
23
23
19
O
OUT1
31
38
25
O
OUT1
30
37
24
O
OUT2
35
45
31
O
OUT2
34
44
30
O
OUT3
38
51
36
O
OUT3
37
50
35
O
OUT4
45
—
—
O
OUT4
44
—
—
O
OUT5
51
—
—
O
OUT5
50
—
—
O
OUT6
54
—
—
O
OUT6
53
—
—
O
OUT7
59
—
—
O
OUT7
58
—
—
O
Output Clocks. These output clocks support a programmable signal amplitude and common mode voltage. Desired output signal format is configurable using register control. Termination
recommendations are provided in “5.8.2. Differential Output Terminations” and “5.8.3. LVCMOS Output Terminations” Unused outputs should be left unconnected.
Notes:
1. Refer to the Si5347/46 Family Reference Manual for more information on register setting names.
2. I = Input, O = Output, P = Power.
3. The IO_VDD_SEL control bit (0x0943 bit 0) selects 3.3 V or 1.8 V operation.
4. The voltage on the VDDS pin(s) determines 3.3 V or 1.8 V operation.
Rev. 1.1
47
Si5347/46
Table 17. Si5347/46 Pin Descriptions1 (Continued)
Pin
Name
Pin Number
Si5347A/B Si5347C/D
Si5346
Pin
Type2
Function
Serial Interface
I2C Select. This pin selects the serial interface mode as I2C
(I2C_SEL = 1) or SPI (I2C_SEL = 0). This pin is internally pulled
high. See Note 3.
I2C_SEL
39
39
38
I
SDA/
SDIO
18
18
13
I/O
Serial Data Interface. This is the bidirectional data pin (SDA) for
the I2C mode, or the bidirectional data pin (SDIO) in the 3-wire SPI
mode, or the input data pin (SDI) in 4-wire SPI mode. When in I2C
mode, this pin must be pulled-up using an external resistor of
> 1 k. No pull-up resistor is needed when in SPI mode.
See Note 3.
A1/SDO
17
17
15
I/O
Address Select 1/Serial Data Output. In I2C mode this pin functions as the A1 address input pin. In 4-wire SPI mode this is the
serial data output (SDO) pin. See Note 3.
SCLK
16
16
14
I
Serial Clock Input. This pin functions as the serial clock input for
both I2C and SPI modes. When in I2C mode, this pin must be
pulled-up using an external resistor of > 1 k. No pull-up resistor is
needed when in SPI mode. See Note 3.
A0/CS
19
19
16
I
Address Select 0/Chip Select. This pin functions as the hardware
controlled address A0 in I2C mode. In SPI mode, this pin functions
as the chip select input (active low). This pin is internally pulled-up.
See Note 3.
Notes:
1. Refer to the Si5347/46 Family Reference Manual for more information on register setting names.
2. I = Input, O = Output, P = Power.
3. The IO_VDD_SEL control bit (0x0943 bit 0) selects 3.3 V or 1.8 V operation.
4. The voltage on the VDDS pin(s) determines 3.3 V or 1.8 V operation.
48
Rev. 1.1
Si5347/46
Table 17. Si5347/46 Pin Descriptions1 (Continued)
Pin
Name
Pin Number
Si5347A/B Si5347C/D
Si5346
Pin
Type2
Function
Control/Status
INTR
12
12
17
O
Interrupt. This pin is asserted low when a change in device status
has occurred. It should be left unconnected when not in use. See
Note 3.
RST
6
6
3
I
Device Reset. Active low input that performs power-on reset (POR)
of the device. Resets all internal logic to a known state and forces
the device registers to their default values. Clock outputs are
disabled during reset. This pin is internally pulled-up. See Note 3.
Output Enable 0. This pin is used to enable (when held low) and
disable (when held high) the output clocks. By default this pin controls all outputs. It can also be configured to control a subset of outputs. See section “5.8.10. Output Enable/Disable” for details. This
pin is internally pulled-down. See Note 3.
OE0
11
11
12
OE1
41
41
—
Output Enable 1. (Si5347) This is an additional output enable pin
that can be configured to control a subset of outputs. By default it
has no control on the outputs until configured. See section “5.8.10.
Output Enable/Disable” for details. There is no internal pull-up/pulldown for this pin. See Note 4. This pin must be pulled up or down
externally (do not leave floating when not in use).
—
—
37
Output Enable 1. (Si5346) This is an additional output enable pin
that can be configured to control a subset of outputs. By default it
has no control on the outputs until configured. See section “5.8.10.
Output Enable/Disable” for details. This pin is internally pulleddown. See Note 3.
LOL_A
3
3
28
O
LOL_B
4
4
27
O
LOL_C
5
5
—
O
LOL_D
47
47
—
O
LOS_XAXB
25
25
33
O
Status Pins. This pin indicates a loss of signal alarm on the XA/XB
pins. This either indicates a XTAL failure or a loss of external signal
on the XA/XB pins. This pin can be left unconnected when unused.
Si5347: See Note 3, Si5346: See Note 3.
DSPLL_SEL0
26
26
—
I
DSPLL_SEL1
27
27
—
I
DSPLL Select Pins (Si5347 only). These pins are used in conjunction with the FINC and FDEC pins. The DSPLL_SEL[1:0] pins determine which DSPLL is affected by a frequency change using the
FINC and FDEC pins. See section “5.4. Digitally-Controlled Oscillator (DCO) Mode” for details. These pins are internally pulled-down.
See Note 3.
I
Loss Of Lock_A/B/C/D. These output pins indicate when DSPLL
A, B, C, D is out-of-lock (low) or locked (high). They can be left
unconnected when not in use. Si5347: See Note 3, Si5346: See
Note 4.
Notes:
1. Refer to the Si5347/46 Family Reference Manual for more information on register setting names.
2. I = Input, O = Output, P = Power.
3. The IO_VDD_SEL control bit (0x0943 bit 0) selects 3.3 V or 1.8 V operation.
4. The voltage on the VDDS pin(s) determines 3.3 V or 1.8 V operation.
Rev. 1.1
49
Si5347/46
Table 17. Si5347/46 Pin Descriptions1 (Continued)
Pin
Name
Pin Number
Si5347A/B Si5347C/D
Si5346
Pin
Type2
Function
FDEC
42
42
—
I
Frequency Decrement Pin (Si5347 only). This pin is used to stepdown the output frequency of a selected DSPLL. The frequency
change step size is register configurable. The DSPLL that is
affected by the frequency change is determined by the DSPLL_SEL[1:0] pins. See Note 4. This pin must be pulled up or down
externally (do not leave floating when not in use).
FINC
48
48
—
I
Frequency Increment Pin (Si5347 only). This pin is used to stepup the output frequency of a selected DSPLL. The frequency
change step size is register configurable. The DSPLL that is
affected by the frequency change is determined by the DSPLL_SEL[1:0] pins. See Note 3. This pin is pulled low internally and can
be left unconnected when not in use.
RSVD
20
20
—
—
21
21
—
—
—
29
—
—
—
30
—
—
—
31
—
—
—
33
—
—
—
34
—
—
—
35
—
—
—
52
—
—
—
53
—
—
—
54
—
—
55
55
—
—
56
56
—
—
—
57
—
—
—
58
—
—
—
59
—
—
28
28
22
—
NC
Reserved. These pins are connected to the die. Leave disconnected.
No Connect. These pins are not connected to the die. Leave disconnected.
Notes:
1. Refer to the Si5347/46 Family Reference Manual for more information on register setting names.
2. I = Input, O = Output, P = Power.
3. The IO_VDD_SEL control bit (0x0943 bit 0) selects 3.3 V or 1.8 V operation.
4. The voltage on the VDDS pin(s) determines 3.3 V or 1.8 V operation.
50
Rev. 1.1
Si5347/46
Table 17. Si5347/46 Pin Descriptions1 (Continued)
Pin
Name
Pin Number
Si5347A/B Si5347C/D
Si5346
Pin
Type2
P
Core Supply Voltage. The device core operates from a 1.8 V supply. See the Si5347/46 Family Reference Manual for power supply
filtering recommendations. A 0402 1 µF capacitor should be placed
very near each of these pins.
Core Supply Voltage 3.3 V. This core supply pin requires a 3.3 V
power source. See the Si5347/46 Family Reference Manual for
power supply filtering recommendations. A 0402 1 µF capacitor
should be placed very near each of these pins.
Function
Power
VDD
32
32
21
46
46
32
60
60
39
—
—
40
13
13
8
P
—
—
9
P
VDDS
40
40
26
P
Status Output Voltage. The voltage on this pin determines VOL/
VOH on the Si5346 LOL_A and LOL_B outputs. On the Si5347, this
pin determines VIL/VIH for the FDEC and OE1 inputs. Connect to
either 3.3 V or 1.8 V. A 0.1 µF bypass capacitor should be placed
very close to this pin.
VDDO0
22
22
18
P
VDDO1
29
36
23
P
VDDO2
33
43
29
P
VDDO3
36
49
34
P
VDDO4
43
—
—
P
Output Clock Supply Voltage 0–7. Supply voltage (3.3 V, 2.5 V,
1.8 V) for OUTn, OUTn outputs. A 0.1 uF bypass capacitor should
be placed very close to this pin. Leave VDDO pins of unused output
drivers unconnected. An alternate option is to connect the VDDO
pin to a power supply and disable the output driver to minimize current consumption. A 0402 1 µF capacitor should be placed very
near each of these pins.
VDDO5
49
—
—
P
VDDO6
52
—
—
P
VDDO7
57
—
—
P
GND PAD
—
—
—
P
VDDA
Ground Pad. This pad provides connection to ground and must be
connected for proper operation. Use as many vias as practical and
keep the via length to an internal ground plan as short as possible.
Notes:
1. Refer to the Si5347/46 Family Reference Manual for more information on register setting names.
2. I = Input, O = Output, P = Power.
3. The IO_VDD_SEL control bit (0x0943 bit 0) selects 3.3 V or 1.8 V operation.
4. The voltage on the VDDS pin(s) determines 3.3 V or 1.8 V operation.
Rev. 1.1
51
Si5347/46
8. Ordering Guide
Ordering Part
Number
Number Of Number of
DSPLLs
Outputs
Si5347A-B-GM1,2
Si5347C-B-GM
0.0001 to 712.5 MHz
4
Si5346A-B-GM1,2
Si5346B-B-GM
0.0001 to 350 MHz
4
Si5347D-B-GM1,2
1,2
Package
RoHS-6,
Pb-Free
Temp
Range
Yes
–40 to 85 °C
—
—
—
—
0.0001 to 712.5 MHz
8
Si5347B-B-GM1,2
1,2
Output Clock
Frequency Range
0.0001 to 350 MHz
0.0001 to 712.5 MHz
2
4
64-Lead
9x9 QFN
0.0001 to 350 MHz
Si5347-EVB
—
—
—
Si5346-EVB
—
—
—
44-Lead
7x7 QFN
Evaluation
Board
Notes:
1. Add an R at the end of the device part number to denote tape and reel ordering options.
2. Custom, factory pre-programmed devices are available. Ordering part numbers are assigned by the ClockBuilder
Pro software. Part number format is: Si5347A-Bxxxxx-GM or Si5346A-Bxxxxx-GM, where “xxxxx” is a unique
numerical sequence representing the pre-programmed configuration.
8.1. Ordering Part Number Fields
Si534fg-Rxxxxx-GM
Timing product family
f = Multi-PLL clock family member (7, 6)
g = Device grade (A, B, C, D)
Product Revision*
Custom ordering part number (OPN) sequence ID**
Package, ambient temperature range (QFN, -40°C to +85°C)
*See Ordering Guide table for current product revision
** 5 digits; assigned by ClockBuilder Pro
52
Rev. 1.1
Si5347/46
9. Package Outlines
9.1. Si5347 9x9 mm 64-QFN Package Diagram
Figure 29 illustrates the package details for the Si5347. Table 18 lists the values for the dimensions shown in the
illustration.
Figure 29. 64-Pin Quad Flat No-Lead (QFN)
Table 18. 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
D2
9.00 BSC
5.10
5.20
e
0.50 BSC
E
9.00 BSC
5.30
E2
5.10
5.20
5.30
L
0.30
0.40
0.50
aaa
—
—
0.15
bbb
—
—
0.10
ccc
—
—
0.08
ddd
—
—
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 Solid State Outline MO-220.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020
specification for Small Body Components.
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9.2. Si5346 7x7 mm 44-QFN Package Diagram
Figure 30 illustrates the package details for the Si5346. Table 19 lists the values for the dimensions shown in the
illustration.
Figure 30. 44-Pin Quad Flat No-Lead (QFN)
Table 19. 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
D2
7.00 BSC
5.10
5.20
e
0.50 BSC
E
7.00 BSC
5.30
E2
5.10
5.20
5.30
L
0.30
0.40
0.50
aaa
—
—
0.15
bbb
—
—
0.10
ccc
—
—
0.08
ddd
—
—
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 Solid State Outline MO-220.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020
specification for Small Body Components.
54
Rev. 1.1
Si5347/46
10. PCB Land Pattern
Figure 31 illustrates the PCB land pattern details for the devices. Table 20 lists the values for the dimensions
shown in the illustration. Refer to the Si5347-46 Family Reference Manual for information about thermal via
recommendations.
Si5347
Si5346
Figure 31. PCB Land Pattern
Table 20. PCB Land Pattern Dimensions
Dimension
Si5347 (Max)
Si5346 (Max)
C1
8.90
6.90
C2
8.90
6.90
E
0.50
0.50
X1
0.30
0.30
Y1
0.85
0.85
X2
5.30
5.30
Y2
5.30
5.30
Notes:
General
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. This Land Pattern Design is based on the IPC-7351 guidelines.
3. All dimensions shown are at Maximum Material Condition (MMC). Least Material Condition is calculated based on a fabrication
Allowance of 0.05 mm.
Solder Mask Design
4. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad is to be
60 µm minimum, all the way around the pad.
Stencil Design
5. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure good solder paste
release.
6. The stencil thickness should be 0.125 mm (5 mils).
7. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads.
8. A 3x3 array of 1.25 mm square openings on 1.80 mm pitch should be used for the center ground pad.
Card Assembly
9. A No-Clean, Type-3 solder paste is recommended.
10. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components.
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Si5347/46
11. Top Marking
Si5347gRxxxxx-GM
YYWWTTTTTT
e4
TW
Line
Characters
1
Si5347gSi5346g-
2
Rxxxxx-GM
3
YYWWTTTTTT
4
Description
Base part number and Device Grade.
Si5347: Quad PLL; 64-QFN
Si5346: Dual PLL; 44-QFN
g = Device Grade. See section “8. Ordering Guide” for more information.
– = Dash character.
R = Product revision. (See section “8. Ordering Guide” for current
revision.)
xxxxx = Customer specific NVM sequence number. (Optional NVM
code assigned for custom, factory pre-programmed devices. Characters are not included for standard, factory default configured
devices). See section “8. Ordering Guide” for more information.
-GM = Package (QFN) and temperature range (–40 to +85 °C).
YYWW = Characters correspond to the year (YY) and work week
(WW) of package assembly.
TTTTTT = Manufacturing trace code.
Circle w/ 1.6 mm (64-QFN) or Pin 1 indicator; left-justified
1.4 mm (44-QFN) diameter
e4
TW
56
Si5346gRxxxxx-GM
YYWWTTTTTT
TW
e4
Pb-free symbol; Center-Justified
TW = Taiwan; Country of Origin (ISO Abbreviation)
Rev. 1.1
Si5347/46
12. Device Errata
Please log in or register at www.silabs.com to access the device errata document.
Rev. 1.1
57
Si5347/46
DOCUMENT CHANGE LIST
Revision 0.9 to Revision 0.95






Removed advanced product information revision
history.
Updated Ordering Guide and changed references to
revision B.
Updated parametric tables 2,3,5,6,7,8 to reflect
production characterization release.
Updated terminology to align with ClockBuilder Pro
software.
Corrected Table 3 references and specifications from
"LVCMOS — DC-coupled" to "Pulsed CMOS — DCcoupled".
Corrected Table 9: I2C data hold time specification to
100 ns from 5 µs.
Revision 0.95 to Revision 1.0














Added 4-Output Si5347C and Si5347D grade
devices to the data sheet.
Corrected AC Test Configuration schematic in Tables
2 and 6.
Corrected minimum input frequency down to
0.008 MHz in Table 3.
Corrected XAXB VIN_DIFF minimum input voltage
swing in Table 3.
Corrected VIN input voltage swing and split into
VIN_DIFF and VIN_SE for differential and singleended inputs in Table 3.
Added FINC/FDEC maximum update rates of 1 MHz
in Table 4.
Added common-mode voltage for 1.8 V sub-LVDS in
Table 5.
Added typical crosstalk spec for Si5346 in Table 5.
Updated TSK, output-to-output skew, in Table 5.
Updated ZO, differential output impedance for Low
Power Mode in Table 5.
Updated LVPECL VOUT maximum value in Table 5.
Adjusted LVCMOS VOH specification in Table 6.
Corrected tSTART, tACQ, and tRDY in Table 8.
Updated SPI timing diagrams and specifications and
removed SPI rise/fall time in Tables 10 and 11.
Revision 1.0 to Revision 1.1

58
Corrected Si5347C/D pin list numbers in Table 17 to
match the pinout.
Rev. 1.1
Si5347/46
CONTACT INFORMATION
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Tel: 1+(512) 416-8500
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Toll Free: 1+(877) 444-3032
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Patent Notice
Silicon Labs invests in research and development to help our customers differentiate in the market with innovative low-power, small size, analogintensive mixed-signal solutions. Silicon Labs' extensive patent portfolio is a testament to our unique approach and world-class engineering team.
The information in this document is believed to be accurate in all respects at the time of publication but is subject to change without notice.
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the use of information included herein. Additionally, Silicon Laboratories assumes no responsibility for the functioning of undescribed features or parameters. Silicon Laboratories reserves the right to make changes without further notice. Silicon Laboratories makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Silicon Laboratories assume any
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Rev. 1.1
59