Si53311 Data Sheet

S i 5 3 3 11
1:6 L O W J I T T E R U NIVERSAL B UFFER /L EVEL
T RANSLATOR WITH 2 : 1 I NPUT M UX (<1.25 GH Z )
Features
Ordering Information:
See page 25.
Applications
Q2
Q3
Q3
Q4
Q4
27
26
25
DIVA
1
24
DIVB
SFOUTA[1]
2
23
SFOUTB[1]
SFOUTA[0]
3
22
SFOUTB[0]
Q0
4
Q0
5
GND
6
19
V DDOB
VDD
7
18
VDDOA
8
17
V REF
14
15
16
CLK1
NC
OEB 13
CLK_SEL
GND
PAD
CLK1
The Si53311 is an ultra low jitter six output differential buffer with pin-selectable
output clock signal format and divider selection. The Si53311 features a 2:1 mux,
making it ideal for redundant clocking applications. The Si53311 utilizes Silicon
Laboratories' advanced CMOS technology to fanout clocks from 1 MHz to
1.25 GHz with guaranteed low additive jitter, low skew, and low propagation delay
variability. The Si53311 features minimal cross-talk and provides superior supply
noise rejection, simplifying low jitter clock distribution in noisy environments.
Independent core and output bank supply pins provide integrated level translation
without the need for external circuitry.
28
Description
29

30

31


Si53311
32


Storage
Telecom
Industrial
Servers
Backplane clock distribution
Q2


11

Pin Assignments
High-speed clock distribution
Ethernet switch/router
Optical Transport Network (OTN)
SONET/SDH
PCI Express Gen 1/2/3
OEA 12

CLK0

Q1

Q1

9

Low output-output skew: <50 ps
Low propagation delay variation:
<400 ps
Independent VDD and VDDO :
1.8/2.5/3.3 V
Excellent power supply noise
rejection (PSRR)
Selectable LVCMOS drive strength to
tailor jitter and EMI performance
Small size: 32-QFN (5 mm x 5 mm)
RoHS compliant, Pb-free
 Industrial temperature range:
–40 to +85 °C
10

6 differential or 12 LVCMOS outputs 
Ultra-low additive jitter: 100 fs rms 
Wide frequency range:
1 MHz to 1.25 GHz

Any-format input with pin selectable
output formats: LVPECL, Low Power 
LVPECL, LVDS, CML, HCSL,
LVCMOS

2:1 mux with hot-swappable inputs
Asynchronous output enable

Output clock division: /1, /2, /4

NC

CLK0

21
Q5
20
Q5
Patents pending
Functional Block Diagram
VREF
Vref
Generator
Power
Supply
Filtering
DIVA
VDDOA
SFOUTA[1:0]
OEA
Q0, Q1, Q2
DivA
Q0, Q1, Q2
CLK0
CLK0
DIVB
VDDOB
SFOUTB[1:0]
OEB
Q3, Q4, Q5
CLK1
CLK1
CLK_SEL
Preliminary Rev. 0.4 10/12
Switching
Logic
DivB
Q3, Q4, Q5
Copyright © 2012 by Silicon Laboratories
Si53311
This information applies to a product under development. Its characteristics and specifications are subject to change without notice.
Si53311
TABLE O F C ONTENTS
Section
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
2. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.1. Universal, Any-Format Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2. Input Bias Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3. Universal, Any-Format Output Buffer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.4. Input Mux and Output Enable Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.5. Flexible Output Divider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.6. Input Mux and Output Enable Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.7. Power Supply (VDD and VDDOX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.8. Output Clock Termination Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
2.9. AC Timing Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.10. Typical Phase Noise Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.11. Input Mux Noise Isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.12. Power Supply Noise Rejection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3. Pin Description: 32-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.1. 5x5 mm 32-QFN Package Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6. PCB Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
6.1. 5x5 mm 32-QFN Package Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7. Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
7.1. Si53311 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
7.2. Top Marking Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
2
Preliminary Rev. 0.4
Si53311
1. Electrical Specifications
Table 1. Recommended Operating Conditions
Parameter
Ambient Operating
Temperature
Supply Voltage Range*
Output Buffer Supply
Voltage*
Symbol
Test Condition
Min
Typ
Max
Unit
–40
—
85
°C
LVDS, CML, HCSL, LVCMOS
1.71
1.8
1.89
V
LVPECL, low power LVPECL,
LVDS, CML, HCSL, LVCMOS
2.38
2.5
2.63
V
2.97
3.3
3.63
V
LVDS, CML, HCSL, LVCMOS
1.71
—
1.89
V
LVPECL, low power LVPECL,
LVDS, CML, HCSL, LVCMOS
2.38
—
2.63
V
2.97
—
3.63
V
TA
VDD
VDDO
*Note: Core supply VDD and output buffer supplies VDDO are independent.
Table 2. Input Clock Specifications
(VDD=1.8 V  5%, 2.5 V  5%, or 3.3 V  10%, TA=–40 to 85 °C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Differential Input Common
Mode Voltage
VCM
VDD = 2.5 V 5%, 3.3 V 10%
0.05
—
—
V
Input Swing
(single-ended, peak-topeak)
VIN
0.1
—
1.1
V
Input Voltage High
VIH
VDD x
0.7
—
—
V
Input Voltage Low
VIL
—
—
VDD x
0.3
V
Input Capacitance
CIN
—
5
—
pF
Preliminary Rev. 0.4
3
Si53311
Table 3. DC Common Characteristics
(VDD = 1.8 V 5%, 2.5 V  5%, or 3.3 V 10%,TA = –40 to 85 C)
Parameter
Supply Current
Output Buffer
Supply Current
(Per Clock Output)
@100 MHz
Leakage Current
Symbol
Test Condition
Min
Typ
Max
Unit
—
TBD
100
mA
LVPECL (3.3 V)
—
35
—
mA
Low Power LVPECL (3.3 V)
—
30
—
mA
LVDS (3.3 V)
—
20
—
mA
CML (3.3 V)
—
30
—
mA
HCSL, 100 MHz, 2 pF load (3.3 V)
—
35
—
mA
CMOS (1.8 V, SFOUT = Open/0),
per output, CL = 5 pF, 200 MHz
—
5
—
mA
CMOS (2.5 V, SFOUT = Open/0),
per output, CL = 5 pF, 200 MHz
—
8
—
mA
CMOS (3.3 V, SFOUT = 0/1),
per output, CL = 5 pF, 200 MHz
—
15
—
mA
Input leakage at all inputs except
CLKIN, VIN = 0 V
—
—
TBD
µA
Input leakage at CLKIN
VIN = 0 V
—
—
TBD
µA
IDD
IDDOX
IL
Voltage Reference
VREF
VREF pin
—
VDD/2
—
V
Input High Voltage
VIH
SFOUTX, DIVX
3-level input pins
0.85 x
VDD
—
—
V
Input Mid Voltage
VIM
SFOUTX, DIVX
3-level input pins
0.45 x
VDD
0.5 x
VDD
0.55 x
VDD
V
Input Low Voltage
VIL
SFOUTX, DIVXpin
3-level input pins
—
—
0.15 x
VDD
V
Internal Pull-down
Resistor
RDOWN
CLK_SEL, DIVA, DIVB, SFOUTA[1],
SFOUTB[1]
—
25
—
kΩ
RUP
SFOUTA[1], SFOUTB[1], DIVA,
DIVB, OEA, OEB
—
25
—
kΩ
Internal Pull-up
Resistor
4
Preliminary Rev. 0.4
Si53311
Table 4. DC Characteristics—LVPECL and Low Power LVPECL
(VDD = 2.5 V  5%, or 3.3 V 10%,TA = –40 to 85 C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Output Voltage High
VOH
RL = 50 Ω to VDDOX – 2 V
VDDOX –
1.145
—
VDDOX –
0.895
V
Output Voltage Low
VOL
RL = 50 Ω to VDDOX – 2 V
VDDOX –
1.945
—
VDDOX –
1.695
V
Output DC Common
Mode Voltage
VCOM
VDDOX –
1.895
—
VDDOX –
1.425
V
0.25
0.60
0.85
V
Single-Ended
Output Swing
VSE
Terminate unused outputs to
RL = 50 Ω to VDDOX – 2 V
Table 5. DC Characteristics—CML
(VDD = 1.8 V 5%, 2.5 V  5%, or 3.3 V 10%,TA = –40 to 85 C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Single-Ended Output
Swing
VSE
Terminated as shown in Figure 6
(CML termination).
300
400
500
mV
Table 6. DC Characteristics—LVDS
(VDD = 1.8 V 5%, 2.5 V  5%, or 3.3 V 10%,TA = –40 to 85 C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Single-Ended Output
Swing
VSE
RL = 100 Ω across QN and QN
247
—
454
mV
Output Common
Mode Voltage
(VDDO=2.5V or 3.3V)
VCOM1
VDDOX = 2.38 to 2.63 V, 2.97 to
3.63 V, RL = 100 Ω across QN
and QN
1.10
1.25
1.35
V
Output Common
Mode Voltage
(VDDO=1.8V)
VCOM2
VDDOX = 1.71 to 1.89 V,
RL = 100 Ω across QN
and QN
0.85
0.97
1.10
V
Preliminary Rev. 0.4
5
Si53311
Table 7. DC Characteristics—LVCMOS
(VDD = 1.8 V 5%, 2.5 V  5%, or 3.3 V 10%,TA = –40 to 85 C)
Parameter
Symbol
*
Output Voltage Low*
Output Voltage High
Test Condition
Min
Typ
Max
Unit
VOH
0.85 x
VDDOX
—
—
V
VOL
—
—
0.15 x
VDDOX
V
*Note: IOH and IOL per the Output Signal Format Table for specific VDDOX and SFOUTX settings.
Table 8. DC Characteristics—HCSL
(VDD = 1.8 V 5%, 2.5 V  5%, or 3.3 V 10%,TA = –40 to 85 C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Output Voltage High
VOH
RL = 50 Ω to GND
550
700
850
mV
Output Voltage Low
VOL
RL = 50 Ω to GND
–150
0
150
mV
Single-Ended
Output Swing
VSE
RL = 50 Ω to GND
—
700
—
mV
Crossing Voltage
VC
RL = 50 Ω to GND
250
350
550
mV
6
Preliminary Rev. 0.4
Si53311
Table 9. AC Characteristics
(VDD = 1.8 V 5%, 2.5 V  5%, or 3.3 V 10%,TA = –40 to 85 C)
Parameter
Frequency
Symbol
Test Condition
Min
Typ
Max
Unit
F
LVPECL, low power LVPECL,
LVDS, CML, HCSL
1
—
1250
MHz
LVCMOS
1
—
200
MHz
200 MHz, 50 toVDD/220/80%
TR/TF<10% of period (LVCMOS)
TBD
TBD
TBD
%
20/80% TR/TF<10% of period
(Differential)
48
50
52
%
0.75
—
—
V/ns
350
ps
DC
Duty Cycle
Note: 50% input duty
cycle.
Minimum Input Clock
Slew Rate1
SR
Required to meet prop delay and
additive jitter specifications
(20–80%)
Output Rise/Fall Time
TR/TF
LVPECL, LVDS, CML, HCSL,
20/80%
200 MHz, 50 20/80%,
2 pF load (LVCMOS)
Minimum Input Pulse
Width
TW
TBD
TBD
750
ps
500
—
—
ps
Additive Jitter
(Differential Clock
Input)
J
VDD = 2.5/3.3 V, LVPECL/LVDS,
F = 725 MHz, 0.75 V/ns
input slew rate
—
60
80
fs
Propagation Delay
TPLH,
TPHL
Low to high, high to low
Single-ended
TBD
—
TBD
ns
Low to high, high to low
Differential
TBD
—
TBD
ns
F = 1 MHz
—
2
—
s
F = 100 MHz
—
60
—
ns
F = 725 MHz
—
50
—
ns
F = 1 MHz
—
2
—
s
F = 100 MHz
—
25
—
ns
F = 725 MHz
—
15
—
ns
Output Enable Time2
Output Disable Time
2
TEN
TDIS
Notes:
1. For clock division applications, a minimum input clock slew rate of 30 mV/ns is required.
2. See Figure 4.
3. Defined as skew between outputs on different devices operating at the same supply voltages, temperatures, and equal
load conditions. Using the same type of inputs on each device, the outputs are measured at the differential cross points.
4. Measured for 156.25 MHz carrier frequency. Sine-wave noise added to VDDOX (1.8V=50mVPP, 2.5/3.3V=100mVPP)
and noise spur amplitude measured. See AN491 for further details.
Preliminary Rev. 0.4
7
Si53311
Table 9. AC Characteristics (Continued)
(VDD = 1.8 V 5%, 2.5 V  5%, or 3.3 V 10%,TA = –40 to 85 C)
Parameter
Output to Output
Skew
Part to Part Skew3
Power Supply Noise
Rejection4
Symbol
Test Condition
Min
Typ
Max
Unit
TSK
Identical Configuration, Singleended (QN to QM)
—
—
100
ps
Identical Configuration,
Differential (QN to QM)
—
—
50
ps
TPS
Identical configuration
—
50
—
ps
PSRR
10 kHz sinusoidal noise
—
–90
—
dBc
100 kHz sinusoidal noise
—
–90
—
dBc
500 kHz sinusoidal noise
—
–80
—
dBc
1 MHz sinusoidal noise
—
–70
—
dBc
Notes:
1. For clock division applications, a minimum input clock slew rate of 30 mV/ns is required.
2. See Figure 4.
3. Defined as skew between outputs on different devices operating at the same supply voltages, temperatures, and equal
load conditions. Using the same type of inputs on each device, the outputs are measured at the differential cross points.
4. Measured for 156.25 MHz carrier frequency. Sine-wave noise added to VDDOX (1.8V=50mVPP, 2.5/3.3V=100mVPP)
and noise spur amplitude measured. See AN491 for further details.
8
Preliminary Rev. 0.4
Si53311
Table 10. Thermal Conditions
Parameter
Symbol
Test Condition
Value
Unit
Thermal Resistance,
Junction to Ambient
JA
Still air
49.6
°C/W
Thermal Resistance,
Junction to Case
JC
Still air
32.3
°C/W
Table 11. Absolute Maximum Ratings
Parameter
Min
Typ
Max
Unit
TS
–55
—
150
C
Supply Voltage
VDD
–0.5
—
3.8
V
Input Voltage
VIN
–0.5
—
VDD+
0.3
V
Output Voltage
VOUT
—
—
VDD+
0.3
V
ESD Sensitivity
HBM
2000
—
—
V
ESD Sensitivity
CDM
500
—
—
V
Peak Soldering Reflow
Temperature
TPEAK
—
—
260
C
—
—
125
C
Storage Temperature
Maximum Junction
Temperature
Symbol
Test Condition
HBM, 100 pF, 1.5 kΩ
Pb-Free; Solder reflow profile per
JEDEC J-STD-020
TJ
Note: Stresses beyond those listed in this table may cause permanent damage to the device. Functional operation
specification compliance is not implied at these conditions. Exposure to maximum rating conditions for extended
periods may affect device reliability.
Preliminary Rev. 0.4
9
Si53311
2. Functional Description
The Si53311 is a low jitter, low skew 1:6 differential buffer with an integrated 2:1 input mux. The device has a
universal input that accepts most common differential or LVCMOS input signals. A clock select pin is used to select
the active input clock. The selected clock input is routed to two independent banks of outputs. Each output bank
features control pins to select signal format, output enable, output divider setting and LVCMOS drive strength.
2.1. Universal, Any-Format Input
The Si53311 has a universal input stage that enables simple interfacing to a wide variety of clock formats, including
LVPECL, LVCMOS, LVDS, HCSL, and CML. Tables 12 and 13 summarize the various input ac- and dc-coupling
options supported by the device. Figures 3 and 4 show the recommended input clock termination options.
Table 12. LVPECL, LVCMOS, and LVDS
LVPECL
LVCMOS
LVDS
AC-Couple
DC-Couple
AC-Couple
DC-Couple
AC-Couple
DC-Couple
1.8 V
N/A
N/A
No
Yes
Yes
No
2.5/3.3 V
Yes
Yes
No
Yes
Yes
Yes
Table 13. HCSL and CML
HCSL
CML
AC-Couple
DC-Couple
AC-Couple
DC-Couple
1.8 V
No
No
Yes
No
2.5/3.3 V
No
Yes (3.3 V)
Yes
No
Si533xx
0.1 uF
CLKx
100
/CLKx
0.1 uF
Figure 1. Differential LVPECL, LVDS, CML AC-Coupled Input Termination
V D D O = 3 .3 V , 2 .5 V , 1 .8 V
V DD
S i5 3 3 x x
CMOS
D riv e r
Rs
CLKx
50
/C L K x
0 .1 u F
V REF
N o te : V D D O a n d V D D m u s t b e a t th e sa m e vo lta g e le ve l.
Figure 2. LVCMOS DC-Coupled Input Termination
10
Preliminary Rev. 0.4
Si53311
VDDO
DC Coupled LVPECL Termination Scheme 1
R1
VDD
R1
VDDO = 3.3V or 2.5V
Si533xx
CLKx
50
“Standard”
LVPECL
Driver
/CLKx
50
R2
R2
3.3V LVPECL: R1 = 127 Ohm, R2 = 82.5 Ohm
VTERM = VDDO – 2V
R1 // R2 = 50 Ohm
2.5V LVPECL: R1 = 250 Ohm, R2 = 62.5 Ohm
DC Coupled LVPECL Termination Scheme 2
VDD
VDDO = 3.3V or 2.5V
Si533xx
50
“Standard”
LVPECL
Driver
CLKx
/CLKx
50
50
50
VTERM = VDDO – 2V
DC Coupled LVDS Termination
VDD
VDDO = 3.3V or 2.5V
Si533xx
CLKx
50
Standard
LVDS
Driver
/CLKx
50
100
DC Coupled HCSL Termination Scheme
VDDO = 3.3V
33
Si533xx
50
Standard
HCSL Driver
VDD
CLKx
/CLKx
33
50
50
50
Note: 33 Ohm series termination is optional depending on the location of the receiver.
Figure 3. Differential DC-Coupled Input Terminations
Preliminary Rev. 0.4
11
Si53311
2.2. Input Bias Resistors
Internal bias resistors ensure a differential output low condition in the event that the clock inputs are not connected.
The noninverting input is biased with a 18.75 k pulldown to GND and a 75 k pullup to VDD. The inverting input is
biased with a 75 k pullup to VDD.
VDD
RPU
RPU
+
RPD
CLK0 or
CLK1
–
RPU = 75 kohm
RPD = 18.75 kohm
Figure 4. Input Bias Resistors
2.3. Universal, Any-Format Output Buffer
The Si53311 has highly flexible output drivers that support a wide range of clock signal formats, including LVPECL,
low power LVPECL, LVDS, CML, HCSL, and LVCMOS. SFOUTX[1] and SFOUTX[0] are 3-level inputs that can be
pin-strapped to select the Bank A and Bank B clock signal formats, respectively. This feature enables the device to
be used for format/level translation in addition to clock distribution, minimizing the number of unique buffer part
numbers required in a typical application and simplifying design reuse. For EMI reduction applications, four
LVCMOS drive strength options are available for each VDDO setting.
Table 14. Output Signal Format Selection
SFOUTX[1]
SFOUTX[0]
VDDOX = 3.3 V
VDDOX = 2.5 V
VDDOX = 1.8 V
Open*
Open*
LVPECL
LVPECL
N/A
0
0
LVDS
LVDS
LVDS
0
1
LVCMOS, 24 mA drive LVCMOS, 18 mA drive
LVCMOS, 12 mA drive
1
0
LVCMOS, 18 mA drive LVCMOS, 12 mA drive
LVCMOS, 9 mA drive
1
1
LVCMOS, 12 mA drive LVCMOS, 9 mA drive
LVCMOS, 6 mA drive
Open*
0
LVCMOS, 6 mA drive
LVCMOS, 4 mA drive
LVCMOS, 2 mA drive
Open*
1
LVPECL Low power
LVPECL Low power
N/A
0
Open*
CML
CML
CML
1
Open*
HCSL
HCSL
HCSL
*Note: SFOUTX[1:0] are 3-level input pins. Tie low for “0” setting. Tie high for “1” setting. When left open, the pin floats
to VDD/2.
12
Preliminary Rev. 0.4
Si53311
2.4. Input Mux and Output Enable Logic
The Si53311 provides two clock inputs for applications that need to select between one of two clock sources. The
CLK_SEL pin selects the active clock input. The table below summarizes the input and output clock based on the
input mux and output enable pin settings.
Table 15. Input Mux and Output Enable Logic
CLK_SEL
CLK0
CLK1
OE1
Q2
L
L
X
H
L
L
H
X
H
H
H
X
L
H
L
H
X
H
H
H
X
X
X
L
L3
Notes:
1. Output enable active high
2. On the next negative transition of CLK0 or CLK1.
3. Single-end: Q=low, Q=high
Differential: Q=low, Q=high
2.5. Flexible Output Divider
The Si53311 provides optional clock division in addition to clock distribution. The divider setting for each bank of
output clocks is selected via 3-level control pins as shown in the table below. Leaving the DIVX pins open will force
a divider value of 1 which is the default mode of operation.
Table 16. Divider Selection
DIVX
Divider Value
Open*
1 (default)
0
2
1
4
*Note: DIVX are 3-level input pins. Tie low for “0” setting. Tie high for “1” setting. When left open, the pin floats to
VDD/2.
Preliminary Rev. 0.4
13
Si53311
2.6. Input Mux and Output Enable Logic
The Si53311 provides two clock inputs for applications that need to select between one of two clock sources. The
CLK_SEL pin selects the active clock input. The table below summarizes the input and output clock based on the
input mux and output enable pin settings.
Table 17. Input Mux and Output Enable Logic
CLK_SEL
CLK0
CLK1
OE1
Q2
L
L
X
H
L
L
H
X
H
H
H
X
L
H
L
H
X
H
H
H
X
X
X
L
L3
Notes:
1. Output enable active high
2. On the next negative transition of CLK0 or CLK1.
3. Single-end: Q=low, Q=high
Differential: Q=low, Q=high
2.7. Power Supply (VDD and VDDOX)
The device includes separate core (VDD) and output driver supplies (VDDOX). This feature allows the core to
operate at a lower voltage than VDDO, reducing current consumption in mixed supply applications. The core VDD
supports 3.3, 2.5, or 1.8 V. Each output bank has its own VDDOX supply, supporting 3.3, 2.5, or 1.8 V.
14
Preliminary Rev. 0.4
Si53311
2.8. Output Clock Termination Options
The recommended output clock termination options are shown below. Unused output clocks should be left floating.
VDDO
DC Coupled LVPECL Termination Scheme 1
R1
R1
VDDO = 3.3V or 2.5V
Si533xx
VDD = VDDO
50
Q
LVPECL
Receiver
Qn
50
R2
VTERM = VDDO – 2V
R1 // R2 = 50 Ohm
R2
3.3V LVPECL: R1 = 127 Ohm, R2 = 82.5 Ohm
2.5V LVPECL: R1 = 250 Ohm, R2 = 62.5 Ohm
DC Coupled LVPECL Termination Scheme 2
VDDO = 3.3V or 2.5V
Si533xx
VDD = VDDO
50
Q
LVPECL
Receiver
Qn
50
50
50
VTERM = VDDO – 2V
VDDO
AC Coupled LVPECL Termination Scheme 1
R1
VDDO = 3.3V or 2.5V
Si533xx
R1
0.1 uF
VDD = 3.3V or 2.5V
50
Q
LVPECL
Receiver
Qn
50
0.1 uF
Rb
R2
Rb
R2
VBIAS = VDD – 1.3V
R1 // R2 = 50 Ohm
3.3V LVPECL: R1 = 82.5 Ohm, R2 = 127 Ohm, Rb = 120 Ohm
2.5V LVPECL: R1 = 62.5 Ohm, R2 = 250 Ohm, Rb = 90 Ohm
AC Coupled LVPECL Termination Scheme 2
VDDO = 3.3V or 2.5V
Si533xx
0.1 uF
VDD = 3.3V or 2.5V
50
Q
LVPECL
Receiver
Qn
50
0.1 uF
Rb
50
Rb
50
3.3V LVPECL: Rb = 120 Ohm
2.5V LVPECL: Rb = 90 Ohm
Figure 5. LVPECL Output Termination
Preliminary Rev. 0.4
15
Si53311
DC Coupled LVDS and Low-Power LVPECL Termination
VDDO= 3.3V or 2.5V or 1.8V
Si533xx
VDD
50
Q
LVDS
Receiver
Qn
50
100
AC Coupled LVDS Termination
VDDO = 3.3V or 2.5V or 1.8V
Si533xx
0.1 uF
VDD
50
Q
LVDS
Receiver
Qn
50
0.1 uF
50
50
AC Coupled CML Termination
VDDO = 3.3V or 2.5V or 1.8V
Si533xx
0.1 uF
VDD
50
Q
CML
Receiver
100
Qn
50
0.1 uF
DC Coupled HCSL Receiver Termination
VDDO = 3.3V
Si533xx
VDD
50
Q
Standard
HCSL
Receiver
Qn
50
50
50
DC Coupled HCSL Source Termination
VDDO = 3.3V
Si533xx
VDD
42.2
50
Q
Qn
42.2
50
86.6
86.6
Figure 6. LVDS, CML, and HCSL Output Termination
16
Preliminary Rev. 0.4
Standard
HCSL
Receiver
Si53311
CMOS
Receivers
Si533xx
CMOS Driver
Zo
Rs
Zout
50
CL = 15 pF
Figure 7. LVCMOS Output Termination
Table 18. Recommended LVCMOS RS Series Termination
SFOUTX[1]
SFOUTX[0]
RS (ohms)
3.3 V
2.5 V
1.8 V
0
1
33
33
33
1
0
33
33
33
1
1
0
0
0
Open
0
0
0
0
Preliminary Rev. 0.4
17
Si53311
2.9. AC Timing Waveforms
TPHL
TSK
CLK
QN
VPP/2
Q
VPP/2
QM
VPP/2
VPP/2
TPLH
TSK
Propagation Delay
Output-Output Skew
TF
Q
80% VPP
20% VPP
80% VPP
Q
20% VPP
TR
Rise/Fall Time
Figure 8. AC Waveforms
18
Preliminary Rev. 0.4
Si53311
2.10. Typical Phase Noise Performance
22.77fs @625MHz
30.26fs @312.5MHz
39.34fs @156.25MHz
Source Jitter
55.00fs @625MHz
106.37fs @312.5MHz
191.58fs @156.25MHz
Total Jitter
Figure 9. Si53311 Phase Noise
Note: Measured single-endedly.
Preliminary Rev. 0.4
19
Si53311
Table 19. Si53311 Additive Jitter
Frequency
(MHz)
Source Jitter
(fs)
Total Jitter
(fs)
Additive Jitter
(fs)
156.25
39.34
191.58
187.50
312.5
30.26
106.37
101.98
625
22.77
55.00
50.07
2.11. Input Mux Noise Isolation
LVPECL [email protected];
Selected clk is active
Unselected clk is static
Mux Isolation = 61dB
LVPECL [email protected];
Selected clk is static
Unselected clk is active
Figure 10. Input Mux Noise Isolation
20
Preliminary Rev. 0.4
Si53311
2.12. Power Supply Noise Rejection
The device supports on-chip supply voltage regulation to reject noise present on the power supply, simplifying low
jitter operation in real-world environments. This feature enables robust operation alongside FPGAs, ASICs and
SoCs and may reduce board-level filtering requirements. For more information, see “AN491: Power Supply
Rejection for Low Jitter Clocks.”
Spur A
Amplitude (dB
Bc)
)F 0+]
Figure 11. Power Supply Noise Rejection (100mVpp Sinusoidal Power Supply Noise Applied)
Preliminary Rev. 0.4
21
Si53311
Q1
Q1
Q2
Q2
Q3
Q3
Q4
Q4
3. Pin Description: 32-Pin QFN
32
31
30
29
28
27
26
25
DIVA
1
24
DIVB
SFOUTA[1]
2
23
SFOUTB[1]
SFOUTA[0]
3
22
SFOUTB[0]
Q0
4
21
Q5
Q0
5
20
Q5
GND
6
19
V DDOB
VDD
7
18
V DDOA
8
17
V REF
15
16
CLK1
NC
14
CLK1
11
CLK0
OEB 13
10
CLK0
OEA 12
9
NC
CLK_SEL
GND
PAD
Table 20. Pin Description
22
Pin
Name
Description
1
DIVA
Output divider control pin for Bank A
Three-level input control. Internally biased at VDD/2. Can be left floating or tied to
ground or VDD.
2
SFOUTA[1]
Output signal format control pin for Bank A
Three-level input control. Internally biased at VDD/2. Can be left floating or tied to
ground or VDD.
3
SFOUTA[0]
Output signal format control pin for Bank A
Three-level input control. Internally biased at VDD/2. Can be left floating or tied to
ground or VDD.
4
Q0
Output clock 0 (complement)
5
Q0
Output clock 0
6
GND
Ground
7
VDD
Core voltage supply.
Bypass with 1.0 F capacitor and place as close to the VDD pin as possible.
Preliminary Rev. 0.4
Si53311
Table 20. Pin Description (Continued)
Pin
Name
Description
8
CLK_SEL
9
NC
No connect.
10
CLK0
Input clock 0
11
CLK0
Input clock 0 (complement)
When the CLK0 is driven by a single-end input, connect VREF to CLK0.
CLK0 contains an internal pull-up resistor.
12
OEA
Output enable—Bank A
When OE=high, the Bank A outputs are enabled.
When OE=low, Q is held low, and Q is held high for differential formats.
For LVCMOS, both Q and Q are held low when OE is set low.
OEA contains an internal pull-up resistor.
13
OEB
Output enable—Bank B
When OE=high, the Bank B outputs are enabled.
When OE=low, Q is held low, and Q is held high for differential formats.
For LVCMOS, both Q and Q are held low when OE is set low.
OEB contains an internal pull-up resistor.
14
CLK1
Input clock 1
15
CLK1
Input clock 1 (complement)
When the CLK1 is driven by a single-end input, connect VREF to CLK1.
CLK1 contains an internal pull-up resistor.
16
NC
17
VREF
18
VDDOA
Output voltage supply—Bank A (Outputs: Q0 to Q2)
Bypass with 1.0 F capacitor and place as close to the VDDOA pin as
possible.
19
VDDOB
Output voltage supply—Bank B (Outputs: Q3 to Q5)
Bypass with 1.0 F capacitor and place as close to the VDDOB pin as
possible.
20
Q5
Output clock 5 (complement)
21
Q5
Output clock 5
Mux input select pin (LVCMOS)
Clock inputs are switched without the introduction of glitches.
When CLK_SEL is high, CLK1 is selected.
When CLK_SEL is low, CLK0 is selected.
CLK_SEL contains an internal pull-down resistor.
No connect.
Input reference voltage
When driven by a LVCMOS clock input, connect the unused clock input to VREF and
a 0.1µF cap to ground. When driven by a differential clock, do not connect the VREF
pin.
Preliminary Rev. 0.4
23
Si53311
Table 20. Pin Description (Continued)
Pin
Name
22
SFOUTB[0]
Output signal format control pin for Bank B.
Three-level input control. Internally biased at VDD/2. Can be left floating or tied to
ground or VDD.
23
SFOUTB[1]
Output signal format control pin for Bank B.
Three-level input control. Internally biased at VDD/2. Can be left floating or tied to
ground or VDD.
24
DIVB
Output divider configuration bit for Bank B.
Three-level input control. Internally biased at VDD/2. Can be left floating or tied to
ground or VDD.
25
Q4
Output clock 4 (complement)
26
Q4
Output clock 4
27
Q3
Output clock 3 (complement)
28
Q3
Output clock 3
29
Q2
Output clock 2 (complement)
30
Q2
Output clock 2
31
Q1
Output clock 1 (complement)
32
Q1
Output clock 1
GND
Pad
GND
24
Description
Ground Pad.
Power supply ground and thermal relief.
Preliminary Rev. 0.4
Si53311
4. Ordering Guide
Part Number
Package
PB-Free, RoHS-6
Temperature
Si53311-B-GM
32-QFN
Yes
–40 to 85 C
Preliminary Rev. 0.4
25
Si53311
5. Package Outline
5.1. 5x5 mm 32-QFN Package Diagram
Figure 12. Si53311 5x5 mm 32-QFN Package Diagram
Table 21. Package Dimensions
Dimension
Min
Nom
Max
A
0.80
0.85
1.00
A1
0.00
0.02
0.05
b
0.18
0.25
0.30
c
0.20
0.25
0.30
D
D2
5.00 BSC
2.00
2.15
e
0.50 BSC
E
5.00 BSC
E2
2.00
2.15
2.30
L
0.30
0.40
0.50
aaa
0.10
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.
26
2.30
Preliminary Rev. 0.4
Si53311
6. PCB Land Pattern
6.1. 5x5 mm 32-QFN Package Land Pattern
Figure 13. Si53311 5x5 mm 32-QFN Package Land Pattern
Table 22. PCB Land Pattern
Dimension
Min
Max
Dimension
Min
Max
C1
4.52
4.62
X2
2.20
2.30
C2
4.52
4.62
Y1
0.59
0.69
Y2
2.20
2.30
E
X1
0.50 BSC
0.20
0.30
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.
Solder Mask Design
1. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad is to
be 60 m minimum, all the way around the pad.
Stencil Design
1. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure good solder
paste release.
2. The stencil thickness should be 0.125 mm (5 mils).
3. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads.
4. A 2x2 array of 0.75 mm square openings on 1.15 mm pitch should be used for the center ground pad.
Card Assembly
1. A No-Clean, Type-3 solder paste is recommended.
2. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components.
Preliminary Rev. 0.4
27
Si53311
7. Top Marking
7.1. Si53311 Top Marking
7.2. Top Marking Explanation
Mark Method:
Laser
Font Size:
2.0 Point (28 mils)
Center-Justified
Line 1 Marking: Device Part Number
53311
Line 2 Marking: Device Revision/Type
B-GM
Line 3 Marking: YY=Year
WW=Work Week
Assigned by the Assembly House.
Corresponds to the year and work
week of the mold date.
Line 4 Marking
28
R=Die Rev
F=Wafer Fab
First two characters of the Manufacturing Code from the Assembly
Purchase Order form.
Circle=0.5 mm Diameter
Lower-Left Justified
Pin 1 Identifier
A=Assembly Site
I=Internal Code
XX=Serial Lot Number
Last four characters of the
Manufacturing Code from the
Assembly Purchase Order form.
Preliminary Rev. 0.4
Si53311
NOTES:
Preliminary Rev. 0.4
29
Si53311
CONTACT INFORMATION
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Austin, TX 78701
Tel: 1+(512) 416-8500
Fax: 1+(512) 416-9669
Toll Free: 1+(877) 444-3032
Please visit the Silicon Labs Technical Support web page:
https://www.silabs.com/support/pages/contacttechnicalsupport.aspx
and register to submit a technical support request.
Patent Notice
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30
Preliminary Rev. 0.4