Si5110 SiPHY® OC-48/STM-16 SONET/SDH Transceiver

S i 5 11 0
SiPHY  OC-48/STM-16 SONET/SDH T RANSCEIVER
Features
Complete low-power, high-speed, SONET/SDH transceiver
integrated limiting amp, CDR, CMU, and MUX/DEMUX.
with
Si5110

Data rates supported:
 SONET-compliant loop-timed
OC-48/STM-16 through 2.7 Gbps
operation
FEC
 Programmable slicing level and
sample phase adjustment
 Low-power operation 1.0 W (typ)


LVDS parallel interface
 DSPLL based clock multiplier unit
 Single supply 1.8 V operation
with selectable loop filter
bandwidths
 11 x 11 mm BGA package
 Integrated limiting amplifier
 Diagnostic and line loopbacks
Bottom View
Ordering Information:
See page 32.
Applications

SONET/SDH transmission
systems


Optical transceiver modules
SONET/SDH test equipment
Description
The Si5110 is a complete low-power transceiver for high-speed serial
communication systems operating between OC-48 and 2.7 Gbps. The
receive path consists of a fully-integrated limiting amplifier, clock and data
recovery unit (CDR), and 1:4 deserializer. The transmit path combines a
low-jitter clock multiplier unit (CMU) with a 4:1 serializer. The CMU uses
Silicon Laboratories’ DSPLL technology to provide superior jitter
performance while reducing design complexity by eliminating external
loop filter components. To simplify BER optimization in long haul
applications, programmable slicing and sample phase adjustment are
supported. The Si5110 operates from a single 1.8 V supply over the
industrial temperature range (–20 to 85 °C).
Functional Block Diagram
RXDIN
Limiting
AMP
PHASEADJ
1:4
DEMUX
SLICELVL
CDR
RXDOUT[3:0]
Diagnostic
Loopback
Line
Loopback
RXCLK
TXCLKOUT
4:1
MUX
÷
TXDOUT
TXDIN[3:0]
DSPLLTM
TX CMU
TXCLK4IN
REFCLK
BWSEL[1:0]
Rev. 1.5 11/12
Copyright © 2012 by Silicon Laboratories
Si5110
S i 5 11 0
2
Rev. 1.5
Si5110
TABLE O F C ONTENTS
Section
Page
1. Detailed Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
3. Typical Application Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5. Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1. Receiver Differential Input Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2. Limiting Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
5.3. Clock and Data Recovery (CDR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.4. Deserialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.5. Voltage Reference Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.6. Auxiliary Clock Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.7. Receive Data Squelch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6. Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.1. DSPLL® Clock Multiplier Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.2. Serialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
7. Loop Timed Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
8. Diagnostic Loopback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
9. Line Loopback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
10. Bias Generation Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
11. Reference Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
12. Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
13. Transmit Differential Output Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
14. Internal Pullups and Pulldowns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
15. Power Supply Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
16. Si5110 Pinout: 99 BGA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
17. Pin Descriptions: Si5110 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
18. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
19. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
20. 11x11 mm 99L PBGA Recommended PCB Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
Rev. 1.5
3
S i 5 11 0
1. Detailed Block Diagram
RXMSBSEL
PHASEADJ
SLICEMODE
SLICELVL
LTR
RXLOL
RXSQLCH
DLBK
LOS
RXDIN
Lim iting
Amp
1:4
DEMUX
CDR
8:4
MUX
RXDOUT[3:0]
LOSLVL
RXCLK1DSBL
LOS
RXCLK1
RXAMPMON
RXCLK2
FIFOERR
RXCLK2DSBL
FIFORST
RXCLK2DIV
TXSQLCH
4:1
MUX
TXDOUT
FIFO
8:4
MUX
TXDIN[3:0]
TXCLKDSBL
TXCLKOUT
TXCLK4OUT
TXCLK4IN
TXLOL
CMU
TXMSBSEL
REFRA TE
REFCLK
REFSEL
BWSEL[1:0]
LPTM LLBK
4
Rev. 1.5
LLBK
Si5110
2. Electrical Specifications
Table 1. Recommended Operating Conditions
Parameter
Min*
Typ
Max*
Unit
TA
–20
25
85
°C
VDDIO
1.71
—
3.47
V
VDD
1.71
1.8
1.89
V
Symbol
Ambient Temperature
LVTTL I/O Supply Voltage
Si5110 Supply Voltage
Test Condition
*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 stated.
V
SIGNAL +
Differential
VICM, VOCM
SIGNAL –
I/Os
VI
VISE, VOSE Single Ended Voltage
0V
(SIGNAL+) – (SIGNAL–)
V
VID,VOD (VID = 2 VISE)
Differential
Voltage Swing
Differential Peak-to-Peak Voltage
t
Figure 1. Differential Voltage Measurement
(RXDIN, RXDOUT, RXCLK1, RXCLK2, TXDIN, TXDOUT, TXCLKOUT, TXCLK4OUT, TXCLK4IN)
tCD
TXDOUT,
TXDIN
tCH
tCP
TXCLKOUT,
TXCLK4IN
RXDOUT
RXCLK1
tcq1
t cq2
Figure 2. Data to Clock Delay
Rev. 1.5
5
S i 5 11 0
80%
All
Differential
IOs
20%
tF
tR
Figure 3. I/O Rise/Fall Times
Table 2. DC Characteristics
(VDD = 1.8 V ±5%, TA = –20 to 85 °C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
IDD
Full Duplex
—
575
640
mA
Line/Diagnostic
Loopback
—
635
700
mA
Full Duplex
—
1.0
1.2
W
Line/Diagnostic
Loopback
—
1.1
1.3
W
VREF driving 10 k
load
1.21
1.25
1.29
V
0.4
0.5
0.6
V
30
—
2000*
mVPPD
0.7
0.9
1.1
V
1000
1200
1400
mVPPD
0.8
1.2
2.4
V
250
—
2400
mVPPD
VLIMIT
0
—
2.5
V
LVDS Input Voltage Level
(TXDIN, TXCLK4IN)
VI
0.8
1.2
2.4
V
LVDS Input Voltage, Differential
(TXDIN, TXCLK4IN)
VID
200
—
—
mVPPD
LVDS Output Voltage Level
(RXDOUT, RXCLK1, RXCLK2,
TXCLK4OUT)
VO
0.925
—
1.475
V
Supply Current
Power Dissipation
PD
Voltage Reference (VREF)
VREF
Common Mode Input Voltage
(RXDIN)
VICM
Differential Input Voltage Swing
(RXDIN)
(at bit error rate of 10–12)
VID
Common Mode Output Voltage
(TXDOUT, TXCLKOUT)
VOCM
Differential Output Voltage Swing
(TXDOUT, TXCLKOUT), Differential pk-pk
VOD
LVPECL Input Common Mode
Voltage (REFCLK)
VICM
LVPECL Input Voltage Swing,
Differential pk-pk (REFCLK)
VID
LVPECL Input Limits
Figure 1
Figure 1
Figure 1
100  Load
Line-to-Line
*Note: Voltage on RXDIN+ or RXDIN– should not exceed 1000 mVPP (single-ended)
6
Rev. 1.5
Si5110
Table 2. DC Characteristics (Continued)
(VDD = 1.8 V ±5%, TA = –20 to 85 °C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
LVDS Output Voltage, Differential
(RXDOUT, RXCLK1, RXCLK2,
TXCLK4OUT)
VOD
100  Load
Line-to-Line
Figure 1
550
650
800
mVPPD
LVDS Common Mode Output
Voltage
(RXDOUT, RXCLK1, RXCLK2,
TXCLK4OUT)
VCM
1.125
1.2
1.275
V
Input Impedance (RXDIN)
RIN
Each input to common mode
42
50
58

LVDS and LVPECL Input Impedance (TXDIN, TXCLK4IN, REFCLK)
RIN
Line to line
90
110
130

CML Output Impedance (TXDOUT, TXCLKOUT)
ROUT
Each output to common mode
45
55
65

LVDS Output Impedance (RXDOUT, RXCLK1, RXCLK2,
TXCLK4OUT)
ROUT
Each output to common mode
45
55
65

Output Current Short to GND
(RXDOUT, RXCLK1, RXCLK2,
TXCLK4OUT)
ISC(–)
—
12
40
mA
Input Impedance
(LOSLVL, SLICELVL, PHASEADJ)
RIN
100
—
—
k
Output Impedance (RXAMPMON)
ROUT
4
6
8
k
Output Current Short to VDD
(RXDOUT, RXCLK1, RXCLK2,
TXCLK4OUT)
ISC(+)
–8
–6
—
mA
LVTTL Input Voltage Low
VIL2
VDDIO = 1.8–3.3 V
–0.3
—
0.35 VDDIO
V
LVTTL Input Voltage High
VIH2
VDDIO = 1.8–3.3 V
0.65 VDDIO
—
VDDIO + 0.3
V
LVTTL Input Impedance
RIN
10
—
—
k
LVTTL Output Voltage Low
(IOUT = 2 mA)
VOL2
VDDIO = 1.8–3.3 V
—
—
0.4
V
LVTTL Output Voltage High
(IOUT = 2 mA)
VOH2
VDDIO = 1.8–3.3 V
VDDIO – 0.45
—
—
V
*Note: Voltage on RXDIN+ or RXDIN– should not exceed 1000 mVPP (single-ended)
Rev. 1.5
7
S i 5 11 0
Table 3. AC Characteristics (RXDIN, RXDOUT, RXCLK1, RXCLK2)
(VDD = 1.8 V ±5%, TA = –20 to 85 °C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
2.41
—
2.7
Gbps
—
622
675
MHz
RXCLK2DIV = 1
RXCLK2DIV = 0
—
—
622
155
675
169
MHz
MHz
tch/tcp, Figure 2
45
—
55
%
Input Data Rate (RXDIN)
Output Clock Frequency (RXCLK1)
fclkout
Output Clock Frequency (RXCLK2)
fclkout
Duty Cycle (RXCLK1, RXCLK2)
Output Rise and Fall Times
(RXCLK1, RXCLK2, RXDOUT)
tR,tF
Figure 3
100
175
250
ps
Data Invalid Prior to RXCLK1
tcq1
Figure 2
—
—
200
ps
Data Invalid After RXCLK1
tcq2
Figure 2
—
—
200
ps
Input Return Loss (RXDIN)
S11
1.25 GHz
2.5 GHz
—
—
–12
–10
—
—
dB
dB
VLOS
LOSLVL = 0–350 mV
0
—
250
mV
—
—
±30
%
0
—
60
mV
—
—
±50
%
SLICELVL = 350 mV
—
–50
—
mV
SLICELVL = 650 mV
—
40
—
mV
SLICELVL = 250 mV
—
–25
—
%
SLICELVL = 750 mV
—
18
—
%
SLICELVL = 200 mV
—
–25
—
%
SLICELVL = 800 mV
—
18
—
%
PHASEADJ = 200 mV
—
–25
—
ps
PHASEADJ = 800 mV
—
25
—
ps
RXDIN = 0–1000 mVPPD
0
—
550
mV
—
±50
—
%
LOS Threshold,
SLICEMODE = 01
LOS Threshold Error,
SLICEMODE = 01
LOS Threshold,
SLICEMODE = 12
VLOS
LOSLVL = 0–500 mV
LOS Threshold Error,
SLICEMODE = 12
Slice Voltage,
SLICEMODE = 03
VLEVEL
Slice Voltage as Percentage of
Differential Input Voltage Swing
(RXDIN), SLICEMODE = 14
VLEVEL
Slice Voltage as Percentage of
Differential Input Voltage Swing
(RXDIN) Error, SLICEMODE = 14
Sample Phase Offset5
RXAMPMON Voltage Range
RXAMPMON Voltage Error
Notes:
1. See Figure 4 on page 15.
2. See Figure 5 on page 16.
3. See Figure 6 on page 16.
4. See Figure 7 on page 17.
5. See Figure 8 on page 17.
8
Rev. 1.5
Si5110
Table 4. AC Characteristics (TXCLK4OUT, TXCLK4IN, TXCLKOUT, TXDIN, TXDOUT)
(VDD = 1.8 V ±5%, TA = –20 to 85 °C)
Parameter
TXCLKOUT Frequency
Symbol
Test Condition
Min
Typ
Max
Unit
fclkout
Figure 2
2.41
—
2.7
GHz
TXCLKOUT Duty Cycle
tch/tcp, Figure 2
40
50
60
%
Output Rise Time
(TXCLKOUT, TXDOUT)
tR
Figure 3
—
50
75
ps
Output Fall Time
(TXCLKOUT, TXDOUT)
tF
Figure 3
—
50
75
ps
TXCLKOUT to TXDOUT Delay
tcd
Figure 2
–42
—
–22
ps
100 kHz–2.5 GHz
2.5 GHz–4.0 GHz
—
—
–12
–10
—
—
dB
dB
—
622
675
MHz
40
—
60
%
Output Return Loss
TXCLK4OUT Frequency
fCLKOUT
TXCLK4OUT Duty Cycle
tch/tcp, Figure 2
TXCLK4OUT Rise & Fall Times
tR,tF
100
175
250
ps
TXDIN Setup to TXCLK4IN
tDSIN
300
—
—
ps
TXDIN Hold from TXCLK4IN
tDHIN
300
—
—
ps
TXCLK4IN Frequency
fCLKIN
—
622
675
MHz
TXCLK4IN Duty Cycle
TXCLK4IN Rise & Fall Times
tch/tcp, Figure 2
tR,tF
40
—
60
%
100
—
300
ps
Table 5. AC Characteristics (Receiver PLL)
(VDD = 1.8 V ±5%, TA = –20 to 85 °C)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Jitter Tolerance
(RXDIN = 100 mVPPD, PRBS31)
JTOL(PP)
f = 10–600 Hz
15*
—
—
UIPP
f = 0.6–6 kHz
15*
—
—
UIPP
—
—
UIPP
*Note: Instrument Limited
Acquisition Time
f = 6–100 kHz
9*
f = 100 kHz–1 MHz
0.4
f = 1–20 MHz
0.3
—
—
UIPP
—
—
2
ms
REFRATE = 1
—
155
169
MHz
REFRATE = 0
—
78
84.4
MHz
TAQ
UIPP
Input Reference Clock Frequency
(REFSEL = 1)
RCFREQ
Reference Clock Duty Cycle
RCDUTY
40
50
60
%
Reference Clock Frequency
Tolerance
RCTOL
–100
—
100
ppm
Frequency Difference at which
Receive PLL goes out of Lock
(REFCLK compared to the
divided down VCO clock)
LOL
610
732
860
ppm
Frequency Difference at which
Receive PLL goes into Lock
(REFCLK compared to the
divided down VCO clock)
LOCK
—
366
240
ppm
Note: Bellcore specifications: GR-253-CORE, Issue 3, September 2000.
Rev. 1.5
9
S i 5 11 0
Table 6. AC Characteristics (Transmitter Clock Multiplier)1
(VDD = 1.8 V ±5%, TA = –20 to 85 °C)
Parameter
Jitter Transfer Bandwidth
OCH48: 2.48832 Gbps
FEC: 2.666676 Gbps
Symbol
Test Condition
Min
Typ
Max
Unit
JBW
BWSEL[1:0] = 00
BWSEL[1:0] = 01
BWSEL[1:0] = 10
BWSEL[1:0] = 11
—
—
—
—
—
—
—
—
12
50
120
200
kHz
kHz
kHz
kHz
—
0.05
0.1
dB
Valid REFCLK
BWSEL[1:0] = 11
—
—
20
ms
REFRATE = 1
—
155
169
MHz
REFRATE = 0
—
78
84.4
MHz
RCDUTY
40
—
60
%
RCTOL
–100
—
100
ppm
Jitter Transfer Peaking
Acquisition Time
TAQ
Input Reference Clock Frequency RCFREQ
Input Reference Clock Duty
Cycle
Input Reference Clock Frequency
Tolerance
Random rms Jitter Generation,
TXCLKOUT (PRBS 31)2
JGEN(rms)
BWSEL[1:0] = 00
BWSEL[1:0] = 01
BWSEL[1:0] = 10
BWSEL[1:0] = 11
2.6
2.0
1.7
1.7
3.7
2.6
2.1
2.1
mUIrms
mUIrms
mUIrms
mUIrms
Random Peak-to-Peak Jitter
Generation, TXCLKOUT
(PRBS 31)2
JGEN(PP)
BWSEL[1:0] = 00
BWSEL[1:0] = 01
BWSEL[1:0] = 10
BWSEL[1:0] = 11
25
23
22
21
36
32
28
27
mUIPP
mUIPP
mUIPP
mUIPP
Notes:
1. Bellcore specifications: GR-253-CORE, Issue 3, September 2000.
2. Full duplex, REFCLK = 155 MHz.
10
Rev. 1.5
Si5110
Table 7. Absolute Maximum Ratings
Parameter
Symbol
Value
Unit
VDD
–0.5 to 2.2
V
VDDIO
–0.5 to 4.0
V
Differential Input Voltage (LVDS Input)
VDIF
5
V
Differential Input Voltage (LVDS Output)
VDIF
–0.3 to (VDD+ 0.3)
V
Differential Input Voltage (LVTTL Input)
VDIF
2.4
V
Differential Input Voltage (LVTTL Output)
VDIF
5
V
±50
mA
DC Supply Voltage
LVTTL I/O Supply Voltage
Maximum Current any output PIN
Operating Junction Temperature
TJCT
–55 to 150
C
Storage Temperature Range
TSTG
–55 to 150
C
ESD HBM (2.5 GHz Pins)
1
kV
ESD HBM Tolerance (100 pF, 1.5 k)
2
kV
Note: Permanent device damage can occur if the above Absolute Maximum Ratings are exceeded. Restrict functional
operation to the conditions as specified in the operational sections of this data sheet. Exposure to absolute maximum
rating conditions for extended periods might affect device reliability.
Table 8. Thermal Characteristics
Parameter
Thermal Resistance Junction to Ambient
Symbol
Test Condition
Value
Unit
JA
Still Air
31
°C/W
Rev. 1.5
11
S i 5 11 0
3. Typical Application Schematic
RXCLK1DSBL
RXCLK2DSBL
RXCLK2DIV
RXMSBSEL
TXMSBEL
DLBK
LLBK
BWSEL[1:0]
LPTM
RXSQLCH
TXSQLCH
REFRATE
REFSEL
TXCLKDSBL
LTR
SLICEMODE
LVTTL
Control Inputs
RXDINAmplitude
MonitorAnalog Output
RXAMPMON
FIFORST
FIFO Over/Underflow
FIFOERR
RESET
TXLOL
0.1 F
High-Speed
Serial Input
LOS
RXDIN±
Si5110
LVPECL Reference
Clock
Loss-of-Lock
Indicator
RXLOL
4
RXDOUT[3:0]±
RXCLK1±
REFCLK
RXCLK2±
LVDSParallel Data
4
Input
0.1 F
TXDIN[3:0]±
Loss-of-Signal
Indicator
LVDS Recovered
Parallel Data
LVDS Recovered
Low-Speed
Clock
High-Speed
Serial Data Output
TXDOUT±
0.1 F
3.091k
1%
Loss-of-Signal Data Slice
Level Set
Level Set
RXREXT
3.091k
1%
Sampling Phase
Level Set
Note* See 15. "Power Supply Filtering" on page 20.
12
Rev. 1.5
TXCLKOUT±
High-Speed
ClockOutput
TXCLK4OUT±
Low-Speed
ClockOutput
GND
VREF
VDD
TXREXT
PHASEADJ
SLICELVL
TXCLK4IN±
LOSLVL
LVDS Data Clock
Input
VDD
Power
Supply
Filtering*
Voltage Reference
Output (1.25 V)
Si5110
4. Functional Description
Equation 1
The Si5110 transceiver is a low-power, fully-integrated
serializer/deserializer that provides significant margin to
all SONET/SDH jitter specifications. The device
operates from 2.4–2.7 Gbps making it suitable for OC48/STM-16
applications,
and
OC-48/STM-16
applications that use 255/238 or 255/237 forward error
correction
(FEC)
coding.
The
low-speed
receive/transmit interface uses a low-power parallel
LVDS interface.
5. Receiver
The receiver within the Si5110 includes a precision
limiting amplifier, a jitter-tolerant clock and data
recovery unit (CDR), and 1:4 demultiplexer.
Programmable data slicing level and sampling phase
adjustment are provided to support bit-error-rate (BER)
optimization for long haul applications.
5.1. Receiver Differential Input Circuitry
The receiver serial input provides proper termination
and biasing through two resistor dividers internal to the
device. The active circuitry has high-impedance inputs
and provides sufficient gain for the clock and data
recovery unit to recover the serial data. The input bias
levels are optimized for jitter tolerance and input
sensitivity and are typically not dc compatible with
standard I/Os; simply ac couple the data lines as shown
in Figure 10.
The receiver signal amplitude monitoring circuit is also
used in the generation of the loss-of-signal alarm (LOS).
5.2.2. Loss-of-Signal Alarm (LOS)
The Si5110 can be configured to activate a loss-ofsignal alarm output (LOS) when the RXDIN input
amplitude drops below a programmable threshold level.
An appropriate level of hysteresis prevents unnecessary
switching on LOS.
The LOS threshold level is set by applying a dc voltage
to the LOSLVL input. The mapping of the voltage on the
LOSLVL pin to the LOS threshold level depends on the
state of the SLICEMODE input. (The SLICEMODE input
is used to select either Absolute Slice mode or
Proportional Slice mode operation.)
The LOSLVL mapping for Absolute Slice Mode
(SLICEMODE = 0) is given in Figure 4 on page 15. The
linear region of the assert can be approximated by the
following equation:
V LOS  V LOSLVL  0.958
Equation 2
where VLOS is the differential pk-pk LOS threshold
referred to the RXDIN input, and VLOSLVL is the voltage
applied to the LOSLVL pin. The linear region of the deassert curve can be approximated by the following
equation:
5.2. Limiting Amplifier
V LOS  V LOSLVL  0.762
The Si5110 incorporates a limiting amplifier with
sufficient gain to directly accept the output of
transimpedance amplifiers.
The limiting amplifier provides sufficient gain to fully
saturate with input signals that are greater than 30 mV
peak-to-peak differential. In addition, input signals up to
2 V peak-to-peak differential do not cause any
performance degradation.
Equation 3
The LOSLVL mapping for Proportional Slice mode
(SLICEMODE = 1) is given in Figure 5 on page 16. The
linear region of the assert can be approximated by the
following equation:
V LOS  V LOSLVL  0.61
5.2.1. Receiver Signal Amplitude Monitoring
The Si5110 limiting amplifier includes circuitry that
monitors the amplitude of the receiver differential input
signal (RXDIN). The RXAMPMON output provides an
analog output signal that is proportional to the input
signal amplitude. The signal is enabled when
SLICEMODE is asserted. The voltage on the
RXAMPMON output is nominally equal to one-half of
the differential peak-to-peak signal amplitude of RXDIN
as shown in Equation 1.
Equation 4
where VLOS is the differential pk-pk LOS threshold
referred to the RXDIN input, and VLOSLVL is the voltage
applied to the LOSLVL pin.
The linear region of the assert curve can be
approximated be the following equation:
V RXAMPMON   V RXDIN  PP   .566 
V LOS  V LOSLVL  0.72
Equation 5
Rev. 1.5
13
S i 5 11 0
The LOS detection circuitry is disabled by tieing the
LOSLVL input to VREF. This forces the LOS output
high.
5.2.3. Slice Level Adjustment
The limiting amplifier allows adjustment of the 0/1
decision threshold, or slice level, to allow optimization of
bit-error-rates (BER) for demanding applications such
as long-haul links. The Si5110 provides two different
modes of slice level adjustment: Absolute Slice mode
and Proportional Slice mode. The mode is selected
using the SLICEMODE input.
In either mode, the slice level is set by applying a dc
voltage to the SLICELVL input. The mapping of the
voltage on the SLICELVL pin to the 0/1 decision
threshold voltage (or slice voltage) depends on the
selected mode of operation.
The SLICELVL mapping for Absolute Slice mode
(SLICEMODE = 0) is given in Figure 6 on page 16. The
linear region of this curve can be approximated by the
following equation:
V LEVEL    V SLICELVL –  VREF  0.4    0.375  – 0.005
5.3. Clock and Data Recovery (CDR)
The Si5110 uses an integrated CDR to recover clock
and data from a non-return to zero (NRZ) signal input on
RXDIN. The recovered clock is used to regenerate the
incoming data by sampling the output of the limiting
amplifier at the center of the NRZ bit period.
5.3.1. Sample Phase Adjustment
In applications where data eye distortions are
introduced by the transmission medium, it may be
desirable to recover data by sampling at a point that is
not at the center of the data eye. The Si5110 provides a
sample phase adjustment capability that allows
adjustment of the CDR sampling phase across the NRZ
data period. When sample phase adjustment is
enabled, the sampling instant used for data recovery
can be moved over a range of approximately ±22 ps
relative to the center of the incoming NRZ bit period.
The sample phase is set by applying a dc voltage to the
PHASEADJ input. The mapping of the voltage present
on the PHASEADJ input to the sample phase sampling
offset is given in Figure 8. The linear region of this curve
can be approximated by the following equation:
Equation 6
where VLEVEL is the effective slice level referred to the
RXDIN input, VSLICELVL is the voltage applied to the
SLICELVL pin, and VREF is the reference voltage
provided by the Si5110 on the VREF output pin
(nominally 1.25 V).
The SLICELVL mapping for Proportional Slice mode
(SLICEMODE = 1) is given in Figure 7 on page 17. The
linear region of this curve can be approximated by the
following equation:
V LEVEL =   V SLICELVL –  VREF  0.4   
 V RXDIN  PP   0.95   –  0.03  V RXDIN  PP  
Equation 8
where Phase Offset is the sampling offset in
picoseconds from the center of the data eye, VPHASEADJ
is the voltage applied to the PHASEADJ pin, and VREF
is the reference voltage provided by the Si5110 on the
VREF output pin (nominally 1.25 V). A positive phase
offset adjusts the sampling point to lead the default
sampling point (the center of the data eye) and a
negative phase offset adjusts the sampling point to lag
the default sampling point.
Data recovery using a sampling phase offset is disabled
by tieing the PHASEADJ input to VREF. This forces a
phase offset of 0 ps to be used for data recovery.
Equation 7
where VLEVEL is the effective slice level referred to the
RXDIN input, VSLICELVL is the voltage applied to the
SLICELVL pin, VREF is the reference voltage provided
by the Si5110 on the VREF output pin, and VRXDIN(PP) is
the peak-to-peak voltage level of the receive data signal
applied to the RXDIN input.
The slice level adjustment function can be disabled by
tieing the SLICELVL input to VREF. When slice level
adjustment is disabled, the effective slice level is set to
0 mV relative to internally biased input common mode
voltage for RXDIN.
14
Phase Offset  85 ps/V   V PHASEADJ –  0.4  VREF  
5.3.2. Receiver Lock Detect
The Si5110 provides lock-detect circuitry that indicates
whether the PLL has achieved frequency lock with the
incoming data. This circuit compares the frequency of a
divided down version of the recovered clock with the
frequency of the supplied reference clock. The Si5110
will use either REFCLK or TXCLK4IN as the reference
clock input signal, depending on the state of the
REFSEL input. If the (divided) recovered clock
frequency deviates from that of the reference clock by
more than the amount specified in Table 5 on page 9,
the CDR is declared out of lock, and the loss-of-lock
(RXLOL) pin is asserted. In this state, the CDR attempts
to reacquire lock with the incoming data stream. During
Rev. 1.5
Si5110
reacquisition, the recovered clock frequency (RXCLK1
and RXCLK2) drifts over a range of approximately
±1000 ppm relative to the supplied reference clock
unless LTR is asserted. The RXLOL output remains
asserted until the frequency of the (divided) recovered
clock differs from the reference clock frequency by less
than the amount specified in Table 5 on page 9.
5.4. Deserialization
The RXLOL output will be asserted automatically if a
valid reference clock is not detected.
The Si5110 provides the capability to select the order in
which the received serial data is mapped to the parallel
output bus RXDOUT[3:0]. The mapping of the receive
bits to the output data word is controlled by the
RXMSBSEL input. When RXMSBSEL is set low, the
first bit received is output on RXDOUT0, and the
following bits are output in order on RXDOUT1 through
RXDOUT3. When RXMSBSEL is set high, the first bit
received is output on RXDOUT3, and the following bits
are output in order on RXDOUT2 through RXDOUT0.
The Si5110 uses a 1:4 demultiplexer to deserialize the
high-speed input. The deserialized data is output on a
4-bit parallel data bus, RXDOUT[3:0], aligned with the
rising edge of RXCLK1.
5.4.1. Serial Input to Parallel Output Relationship
The RXLOL output will also be asserted whenever the
loss of signal alarm (LOS) is active, provided that the
LTR input is set high (i.e., provided that the device is not
configured for Lock-to-Reference mode).
5.3.3. Lock-to-Reference
The lock-to-reference (LTR) input can be utilized to
ensure the presence of a stable output clock during a
loss-of-signal alarm (LOS). When LTR is asserted, the
CDR is prevented from phase locking to the data signal
and the CDR locks the RXCLKOUT1 and RXCLKOUT2
outputs to the reference clock. In typical applications,
the LOS output is tied to the LTR input to force a stable
output clock during a loss-of-signal condition.
5.5. Voltage Reference Output
The Si5110 provides an output voltage reference that
can be used by external circuitry to set the LOS
threshold, slicing level, or sampling phase adjustment
input voltage levels. One possible implementation uses
a resistor divider to set the control voltage for the
LOSLVL, SLICELVL, or PHASEADJ inputs. An
alternative is the use of digital-to-analog converters
(DACs) to set the control voltages. Using this approach,
VREF is used to set the range of the DAC outputs. The
voltage on the VREF output is nominally 1.25 V.
350
300
250
VLOS (mV)
200
=
V
58
.9
VL
SL
LO
Assert
DeAssert
S
LO
150
V LOS
2
76
=.
VL
SL
LO
100
50
0
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
LOSLV (V)
Figure 4. Typical LOSLVL Transfer Curve, Absolute Slice Mode (SLICEMODE = 0)
Rev. 1.5
15
S i 5 11 0
LOSLVL Transfer Curve (Proportional Slice Mode)
350
300
VLOS (mV)
250
200
V LOS
2 LO
= .7
150
V LOS
L
SLV
L
SLV
1 LO
= .6
100
50
0
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
LOSLVL (V)
LOS Assert Threshold
LOS De-assert Threshold
Figure 5. Typical LOSLVL Transfer Curve, Proportional Slice Mode (SLICEMODE = 1)
SLICELVL Transfer Curve (Absolute Slice Mode)
60
Slice Adjustment (mV)
40
20
0
-20
-40
-60
0.35
0.4
0.45
0.5
0.55
0.6
0.65
SLICELVL (V)
Figure 6. Typical SLICELVL Transfer Curve, Absolute Slice Mode (SLICEMODE = 0)
16
Rev. 1.5
Si5110
SLICELVL Transfer Curve (Proportional Slice Mode)
30
Slice Adjustment (% of RXDIN)
20
10
0
-10
-20
-30
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
0.65
0.7
0.75
SLICELVL (V)
Figure 7. Typical SLICELVL Transfer Curve, Proportional Slice Mode (SLICEMODE = 1)
PHASEADJ Transfer Curve
40
30
Phase Adjustment (ps)
20
10
0
-10
-20
-30
-40
0.2
0.3
0.4
0.5
0.6
0.7
0.8
PHASEADJ (Volts)
Figure 8. Typical PHASEADJ Transfer Curve
Rev. 1.5
17
S i 5 11 0
5.6. Auxiliary Clock Output
6.1. DSPLL® Clock Multiplier Unit
To support the widest range of system timing
configurations, The Si5110 provides a primary clock
output on RXCLK1 and a secondary clock output
(RXCLK2). The RXCLK2 output can be configured to
provide a clock that is 1/4th or 1/16th the frequency of
the high-speed recovered clock. The divide ratio which
determines the RXCLK2 output frequency is selected by
RXCLK2DIV.
The Si5110’s clock multiplier unit (CMU) uses Silicon
Laboratories proprietary DSPLL technology to achieve
optimal jitter performance. The DSPLL implementation
utilizes a digital signal processing (DSP) algorithm to
replace the loop filter commonly found in analog PLL
designs. This algorithm processes the phase detector
error term and generates a digital control value to adjust
the frequency of the voltage-controlled oscillator (VCO).
The DSPLL implementation requires no external loop
filter components. Eliminating sensitive noise entry
points makes the DSPLL implementation less
susceptible to board-level noise sources and makes
SONET/SDH jitter compliance easier to attain in the
application.
5.7. Receive Data Squelch
During some system error conditions, such as LOS, it
may be desirable to force the receive data output to
zero in order to avoid propagation of erroneous data
into the downstream electronics. The Si5110 provides a
data squelching control input, RXSQLCH, for this
purpose.
When the RXSQLCH input is low, the data outputs
RXDOUT[3:0] are forced to a zero state. The
RXSQLCH input is ignored when the device is operating
in Diagnostic Loopback mode (DLBK = 0).
6. Transmitter
The transmitter consists of a low jitter clock multiplier
unit (CMU) with a 4:1 serializer. The CMU uses a
phase-locked loop (PLL) architecture based on Silicon
Laboratories’ proprietary DSPLL technology. This
technology generates ultra-low jitter clock and data
outputs that provide significant margin to the
SONET/SDH specifications. The DSPLL architecture
also utilizes a digitally implemented loop filter that
eliminates the need for external loop filter components.
As a result, sensitive noise coupling nodes that typically
degrade jitter performance in crowded PCB
environments are removed.
The DSPLL also reduces the complexity and relaxes
the performance requirements for reference clock
distribution circuitry for OC-48/STM-16 optical port
cards. The DSPLL provides selectable wideband and
narrowband loop filter settings that allow the jitter
attenuation characteristics of the CMU to be optimized
for the jitter content of the supplied reference clock. This
allows the CMU to operate with reference clocks that
have relatively high jitter content.
Unlike traditional analog PLL implementations, the loop
filter bandwidth of the Si5110 transmitter CMU is
controlled by a digital filter inside the DSPLL circuit
allowing the bandwidth to be changed without changing
any external component values.
18
The transmit CMU multiplies the frequency of the
selected reference clock up to the serial transmit data
rate. The TXLOL output signal provides an indication of
the transmit CMU lock status. When the CMU has
achieved lock with the selected reference, the TXLOL
output is deasserted (driven high). The TXLOL signal
will be asserted, indicating a transmit CMU loss-of-lock
condition, when a valid clock signal is not detected on
the selected reference clock input. The TXLOL signal
will also be asserted during the transmit CMU frequency
calibration. Calibration is performed automatically when
the Si5110 is powered on, when a valid clock signal is
detected on the selected reference clock input following
a period when no valid clock was present, or when the
frequency of the selected reference clock is outside of
the transmit CMU’s PLL lock range or after RESET is
deasserted.
6.1.1. Programmable Loop Filter Bandwidth
The digitally implemented loop filter allows for four
transmit CMU loop bandwidth settings that provide
wideband or narrowband jitter transfer characteristics.
The filter bandwidth is selected via the BWSEL[1:0]
control inputs. The loop bandwidth choices are listed in
Table 6. Unlike traditional PLL implementations,
changing the loop filter bandwidth of the Si5110 is
accomplished without the need to change external
component values.
Lower loop bandwidth settings (Narrowband operation)
make the Si5110 more tolerant to jitter on the reference
clock source. As a result, circuitry used to generate and
distribute the physical layer reference clocks can be
simplified without compromising margin to the
SONET/SDH jitter specifications.
Higher loop bandwidth settings (Wideband operation)
are useful in applications where the reference clock is
provided by a low jitter source like the Si5364 Clock
Synchronization IC or Si5320 Precision Clock
Rev. 1.5
Si5110
Multiplier/Jitter Attenuator IC. Wideband operation
allows the DSPLL to more closely track the precision
reference source, resulting in the best possible jitter
performance.
6.2. Serialization
The Si5110 serialization circuitry is comprised of a FIFO
and a parallel to serial shift register. Low-speed data on
the parallel 4-bit input bus, TXDIN[3:0], is latched into
the FIFO on the rising edge of TXCLK4IN. Data is
clocked out of the FIFO and into the shift register by
TXCLK4OUT. The high-speed serial data stream
TXDOUT is clocked out of the shift register by
TXCLKOUT. The TXCLK4OUT clock is provided as an
output signal to support data word transfers between
the Si5110 and upstream devices using a counter
clocking scheme.
6.2.1. Input FIFO
The Si5110 FIFO decouples the timing of the data
transferred into the device via TXCLK4IN from the data
transferred into the shift register via TXCLK4OUT. The
FIFO is eight parallel words deep and accommodates
any static phase delay that may be introduced between
TXCLK4OUT and TXCLK4IN in counter clocking
schemes. Furthermore, the FIFO accommodates a
bounded phase drift, or wander, between TXCLK4IN
and TXCLK4OUT of up to three parallel data words.
The FIFO circuitry indicates an overflow or underflow
condition by asserting the FIFOERR signal. This output
can be used to re-center the FIFO read/write pointers by
tieing it directly to the FIFORST input.
The FIFORST signal causes re-centering of the FIFO
read/write pointers. The Si5110 also automatically recenters the read/write pointers after the device is
powered on, after an external reset via the RESET
input, and each time the DSPLL transitions from an outof-lock state to a locked state (when TXLOL transitions
from low to high).
6.2.2. Parallel Input To Serial Output Relationship
The Si5110 provides the capability to select the order in
which the data received on the parallel input bus
TXDIN[3:0] is transmitted serially on the high-speed
serial data output TXDOUT. Data on the parallel bus will
be transmitted MSB first or LSB first depending on the
setting of the TXMSBSEL input. When TXMSBSEL is
set low, TXDIN0 is transmitted first, followed in order by
TXDIN1 through TXDIN3. When TXMSBSEL is set
high, TXDIN3 is transmitted first, followed in order by
TXDIN2 through TXDIN0. This feature can simplify
printed circuit board (PCB) routing in applications where
ICs are mounted on both sides of the PCB.
6.2.3. Transmit Data Squelch
To prevent the transmission of corrupted data into the
network, the Si5110 provides a control pin that can be
used to force the high-speed serial data output
TXDOUT to zero. When the TXSQLCH input is set low,
the TXDOUT signal is forced to a zero state. The
TXSQLCH input is ignored when the device is operating
in Line Loopback mode (LLBK = 0).
6.2.4. Clock Disable
The Si5110 provides a clock disable pin, TXCLKDSBL,
that can be used to disable the high-speed serial data
clock output, TXCLKOUT. When the TXCLKDSBL pin is
asserted, the positive and negative terminals of
CLKOUT are tied internally to 1.5 V through 50  onchip resistors.
This feature can be used to reduce power consumption
in applications that do not use the high-speed transmit
data clock.
7. Loop Timed Operation
The Si5110 can be configured to provide SONET/SDH
compliant loop timed operation. When the LPTM input is
set low, the transmit clock and data timing is derived
from the CDR recovered clock output. This is achieved
by dividing down the recovered clock and using it as a
reference source for the transmit CMU. This results in
transmit clock and data signals that are locked to the
timing recovered from the received data path. A narrowband loop filter setting is recommended for this mode of
operation.
8. Diagnostic Loopback
The Si5110 provides a Diagnostic Loopback mode that
establishes a loopback path from the serializer output to
the deserializer input. This provides a mechanism for
looping back data input via the low speed transmit
interface TXDIN[3:0] to the low speed receive data
interface RXDOUT[3:0]. This mode is enabled when the
DLBK input is set low.
Note: Setting both DLBK and LLBK low simultaneously is not
supported.
9. Line Loopback
The Si5110 provides a Line Loopback mode that
establishes a loopback path from the high-speed
receive input to the high-speed transmit output. This
provides a mechanism for looping back the high-speed
data and clock recovered from RXDIN to the transmit
data output TXDOUT and transmit clock TXCLKOUT.
This mode is enabled when the LLBK input is set low.
Note: Setting both DLBK and LLBK low simultaneously is not
supported.
Rev. 1.5
19
S i 5 11 0
10. Bias Generation Circuitry
12. Reset
The Si5110 uses two external resistors, RXREXT and
TXREXT, to set internal bias currents for the receive
and transmit sections of the device, respectively. The
external resistors allow precise generation of bias
currents, which can significantly reduce power
consumption. The bias generation circuitry requires two
3.09 k (1%) resistors each connected between
RXREXT and GND, and between TXREXT and GND.
The Si5110 is reset by holding the RESET pin low for at
least 1 µs. When RESET is asserted, the input FIFO
pointers are reset and the digital control circuitry is
initialized.
11. Reference Clock
The Si5110 supports operation with one of two possible
reference clock sources. In the first configuration, an
external reference clock is connected to the REFCLK
input. The second configuration uses the parallel data
clock, TXCLK4IN, as the reference clock source. The
REFSEL input is used to select whether the REFCLK or
the TXCLK4IN input will be used as the reference clock.
When REFCLK is selected as the reference clock
source (REFSEL = 1), two possible reference clock
frequencies are supported. The reference clock
frequency provided on the REFCLK input can be either
1/16th or 1/32nd the desired transceiver data rate. The
REFCLK frequency is selected using the REFRATE
input.
The TXCLK4IN clock frequency is equal to 1/4th the
transceiver data rate. When TXCLK4IN is selected as
the reference clock source (REFSEL = 0), the
REFRATE input has no effect.
The CMU in the Si5110’s transmit section multiplies the
provided reference up to the serial transmit data rate.
When the CMU has achieved lock with the selected
reference, the TXLOL output is deasserted (driven
high).
The CDR in the receive section of the Si5110 uses the
selected reference clock to center the receiver PLL
frequency in order to speed lock acquisition. When the
receive CDR locks to the data input, the RXLOL signal
is deasserted (driven high).
When RESET transitions high to start normal operation,
the transmit CMU calibration is performed.
13. Transmit Differential Output
Circuit
The Si5110 utilizes a current-mode logic (CML)
architecture to drive the high-speed serial output clock
and data on TXCLKOUT and TXDOUT. An example of
output termination with ac coupling is shown in Figure 9.
In applications where direct dc coupling is possible, the
0.1 F capacitors may be omitted. The differential peakto-peak voltage swing of the CML architecture is listed
in Table 2 on page 6.
14. Internal Pullups and Pulldowns
On-chip 30 k resistors are used to individually set the
LVTTL inputs if these inputs are left disconnected. The
specific default state of each input is enumerated in 17.
"Pin Descriptions: Si5110" on page 25.
15. Power Supply Filtering
The transmitter generated jitter is most sensitive to
power supply noise below its PLL loop-bandwidth
(BWSEL setting). The power supply noise of interest is
bounded between the SONET/SDH generated jitter
specification of 12 kHz (for 2.48832 Gbps) and the PLL
loop-bandwidth. Integrated supply noise from 1/10th the
SONET/SDH specification (1.2 kHz) to 10x the loopbandwidth should be suppressed to a level appropriate
for each design. Below the PLL loop-bandwidth, the
typical generated jitter due to supply noise is
approximately 2.5 mUIpp per 1 mVrms; this parameter
can be used as a guideline for calculating the output
jitter and supply filtering requirements. The receiver
does not place additional power supply constraints
beyond those listed for the transmitter.
Please contact Silicon Laboratories’ applications
engineering for recommendations on bypass capacitors
and their placement.
20
Rev. 1.5
Si5110
1.5 V
VDD
50 
50 
50 
0.1 F
Zo = 50 
0.1 F
Zo = 50 
50 
VDD
24 mA
Figure 9. CML Output Driver Termination (TXCLKOUT, TXDOUT)
1.5 V
0.1 F
150
150
RXDIN+
+
RXDIN–
0.1 F
–
75
75
Figure 10. Receiver Differential Input Circuitry
Rev. 1.5
21
S i 5 11 0
ESD
5 k
In +
100 
In
_
5 k
ESD
Common Mode
Adjust Circuit
Figure 11. LVDS Differential Input Circuitry
6.5 mA
In +
Out +
In _
ESD
50 
50 
+_
1.2 V
In _
Out _
In +
ESD
6.5 mA
Figure 12. LVDS Driver Termination (RXDOUT, TXCLK4OUT)
22
Rev. 1.5
Si5110
16. Si5110 Pinout: 99 BGA
10
9
8
7
6
4
3
2
RXDOUT[0]+ RXDOUT[1]+
RXCLK2+
RXCLK2–
RSVD_GND
RXSQLCH
RXREXT
SLICELVL
PHASEADJ
RXDOUT[0]–
RXCLK1+
RXCLK1–
RSVD_GND
RXAMPMON
VREF
LOSLVL
GND
RXDIN+
B
RXDOUT[2]+ RXDOUT[3]+
RXCLK2DIV
RXCLK2DSBL
SLICEMODE
RSVD_GND
LTR
RXLOL
GND
RXDIN–
C
RXDOUT[2]–
RXDOUT[3]–
RXMSBSEL
VDD
VDD
VDD
VDD
RXCLK1DSBL
LOS
GND
D
REFCLK+
GND
GND
GND
VDD
VDD
VDD
RESET
GND
TXCLKOUT+
E
REFCLK–
GND
GND
GND
VDD
VDD
VDD
REFRATE
GND
TXCLKOUT–
F
TXDIN[2]+
TXDIN[3]+
LPTM
VDD
VDD
VDD
VDD
RSVD_GND
VDDIO
GND
G
TXDIN[2]–
TXDIN[3]–
LLBK
DLBK
BWSEL0
FIFORST
TXMSBSEL
BWSEL1
GND
TXDOUT+
H
TXDIN[0]+
TXDIN[1]+
TXCLKDSBL
REFSEL
TXSQLCH
FIFOERR
RSVD_GND
RSVD_GND
GND
TXDOUT–
J
TXDIN[0]–
TXDIN[1]–
TXCLK4IN+
TXCLK4IN–
TXLOL
TXREXT
RSVD_GND
GND
K
RXDOUT[1]–
5
TXCLK4OUT+ TXCLK4OUT–
1
A
Figure 13. Si5110 Pin Configuration (Bottom View)
Rev. 1.5
23
S i 5 11 0
1
A
2
3
4
5
6
PHASEADJ
SLICELVL
RXREXT
RXSQLCH
RSVD_GND
7
8
9
10
RXCLK2–
RXCLK2+
RXDOUT[1]+
RXDOUT[0]+
RXDOUT[1]– RXDOUT[0]–
B
RXDIN+
GND
LOSLVL
VREF
RXAMPMON
RSVD_GND
RXCLK1–
RXCLK1+
C
RXDIN–
GND
RXLOL
LTR
RSVD_GND
SLICEMODE
RXCLK2DSBL
RXCLK2DIV
RXDOUT[3]+
D
GND
LOS
RXCLK1DSBL
VDD
VDD
VDD
VDD
RXMSBSEL
RXDOUT[3]– RXDOUT[2]–
E
TXCLKOUT+
GND
RESET
VDD
VDD
VDD
GND
GND
GND
REFCLK+
F
TXCLKOUT–
GND
REFRATE
VDD
VDD
VDD
GND
GND
GND
REFCLK–
G
GND
VDDIO
RSVD_GND
VDD
VDD
VDD
VDD
LPTM
TXDIN[3]+
TXDIN[2]+
H
TXDOUT+
GND
BWSEL1
TXMSBSEL
FIFORST
BWSEL0
DLBK
LLBK
TXDIN[3]–
TXDIN[2]–
J
TXDOUT–
GND
RSVD_GND
RSVD_GND
FIFOERR
TXSQLCH
REFSEL
TXCLKDSBL
TXDIN[1]+
TXDIN[0]+
K
GND
RSVD_GND
TXREXT
TXLOL
TXCLK4IN–
TXCLK4IN+
TXDIN[1]–
TXDIN[0]–
TXCLK4OUT– TXCLK4OUT+
Figure 14. Si5110 Pin Configuration (Transparent Top View)
24
Rev. 1.5
RXDOUT[2]+
Si5110
17. Pin Descriptions: Si5110
Pin
Number(s)
Name
I/O
Signal Level
H3
H6
BWSEL1
BWSEL0
I
LVTTL
Description
Transmit DSPLL Bandwidth Select.
The inputs select loop bandwidth of the Transmit
Clock Multiplier DSPLL as listed in Table 6.
Note: Both inputs have an internal pulldown.
H7
DLBK
I
LVTTL
Diagnostic Loopback.
When this input is low, the transmit clock and data are
looped back for output on RXDOUT, RXCLK1 and
RXCLK2. This pin should be held high for normal
operation.
Note: This input has an internal pullup.
J5
FIFOERR
O
LVTTL
FIFO Error.
This output is asserted (driven low) when a FIFO overflow/underflow has occurred. This output is low until
reset by asserting FIFORST.
H5
FIFORST
I
LVTTL
FIFO RESET.
When this input is low, the read/write FIFO pointers
are reset to their initial state.
Note: This input has an internal pullup.
B2, C2, D1,
E2, E7–9,
F2, F7–9,
G1, H2, J2,
K1
GND
GND
H8
LLBK
I
Supply Ground.
Connect to system GND. Ensure a very low
impedance path for optimal performance.
LVTTL
Line Loopback.
When this input is low, the recovered clock and data
are looped back for output on TXDOUT, and TXCLKOUT. Set this pin high for normal operation.
Note: This input has an internal pullup.
D2
LOS
O
B3
LOSLVL
I
LVTTL
Loss-of-Signal.
This output is asserted (driven low) when the peak-topeak signal amplitude on RXDIN is below the threshold set via LOSLVL.
LOS Threshold Level.
Applying an analog voltage to this pin allows adjustment of the Threshold used to declare LOS. Tieing
this input to VREF disables LOS detection and forces
the LOS output high.
Rev. 1.5
25
S i 5 11 0
Pin
Number(s)
Name
I/O
Signal Level
G8
LPTM
I
LVTTL
Description
Loop Timed Operation.
When this input is set low, the recovered clock from
the receiver is divided down and used as the reference source for the transmit CMU. The narrowband
setting for the DSPLL CMU is sufficient to provide
SONET compliant jitter generation and jitter transfer
on the transmit data and clock outputs (TXDOUT,TXCLKOUT). Set this pin high for normal operation.
Note: This input has an internal pullup.
C4
LTR
I
LVTTL
Lock-to-Reference.
When the LTR input is set low, the receiver PLL will
lock to the selected reference clock. This function can
be used to force a stable output clock on the RXCLK1
and RXCLK2 outputs when no valid input data signal
is applied to RXDIN.
When the LTR input is set high, the receiver PLL will
lock to the RXDIN signal (normal operation).
Note: This input has an internal pullup.
A2
PHASEADJ
I
E10
F10
REFCLK+,
REFCLK–
I
Sampling Phase Adjust.
Applying an analog voltage to this pin allows adjustment of the sampling phase across the data eye.
Tieing this input to VREF nominally centers the sampling phase.
LVPECL
Differential Reference Clock.
This input is used as the Si5110 reference clock when
the REFSEL input is set high (REFSEL = 1). The reference clock sets the operating frequency of the
Si5110 transmit CMU, which is used to generate the
high-speed transmit clock TXCLKOUT. The reference
clock is also used by the Si5110 receiver CDR to center the PLL during lock acquisition, and as a reference
for determination of the receiver lock status.
The REFCLK frequency is either 1/16th or 1/32nd of
the serial data rate (nominally 155 or 78 MHz,
respectively). The REFCLK frequency is selected
using the REFRATE input.
When REFSEL = 1, a valid reference clock must be
present.
26
Rev. 1.5
Si5110
Pin
Number(s)
Name
I/O
Signal Level
F3
REFRATE
I
LVTTL
Description
Reference Clock Rate Select.
The REFRATE input sets the frequency for the
REFCLK input. When REFRATE is set high, the
REFCLK frequency is 1/16th the serial data rate
(nominally 155 MHz). When REFRATE is set low, the
REFCLK frequency is 1/32nd the serial data rate
(nominally 78 MHz).
The REFRATE input has no effect when the REFSEL
input is set low.
Note: This input has an internal pullup.
J7
REFSEL
I
LVTTL
Reference Clock Selection.
This input selects the reference clock source to be
used by the Si5110 transmitter and receiver. The reference clock sets the operating frequency of the
Si5110 transmit CMU, which is used to generate the
high-speed transmit clock TXCLKOUT. The reference
clock is also used by the Si5110 receiver CDR to center the PLL during lock acquisition, and as a reference
for determination of the receiver lock status.
When REFSEL = 0, the low-speed data input clock,
TXCLK4IN, is used as the reference clock. When
REFSEL = 1, the reference clock provided on
REFCLK is used.
Note: This input has an internal pullup.
E3
RESET
I
LVTTL
Device Reset.
Forcing this input low for at least 1 s causes a device
reset. For normal operation, this pin should be held
high.
Note: This input has an internal pullup.
A6, B6, C5,
G3, J3–4,
K2
RSVD_GND
B5
RXAMPMON
O
Analog
Receiver Amplitude Monitor.
The RXAMPMON output provides an analog output
signal that is proportional to the input signal
amplitude. See Equation 1 for the relationship
between RXAMPON and RXDIN. This signal is active
when SLICEMODE is asserted.
B8
B7
RXCLK1+,
RXCLK1–
O
LVDS
Differential Receiver Clock Output 1.
The clock recovered from the signal present on
RXDIN is divided down to the parallel output word rate
and output on RXCLK1. In the absence of data, a stable clock on RXCLK1 can be maintained by asserting
LTR.
Reserved Tie To Ground.
Must be connected directly to GND for proper
operation.
Rev. 1.5
27
S i 5 11 0
Pin
Number(s)
Name
I/O
Signal Level
A8
A7
RXCLK2+,
RXCLK2–
O
LVDS
Differential Receiver Clock Output 2.
An auxiliary output clock is provided on this pin that is
equivalent to, or a submultiple of, the output word rate.
The divide factor used in generating RXCLK2 is set
via RXCLK2DIV.
C8
RXCLK2DIV
I
LVTTL
RXCLK2 Clock Divider Select.
This input selects the divide factor used to generate
the RXCLK2 output. When this input is driven high,
RXCLK2 is equal to the output word rate on RXDOUT.
When driven low, RXCLK2 is 1/4th the output word
rate.
Description
Note: This input has an internal pullup.
D3
RXCLK1DSBL
I
LVTTL
RXCLK1 Disable.
Setting this input low disables the RXCLK1 output.
This is used to save power in applications that do not
require the primary output clock.
Note: This input has an internal pullup.
C7
RXCLK2DSBL
I
LVTTL
RXCLK2 Disable.
Setting this input low disables the RXCLK2 output.
This saves power in applications that do not require
an auxiliary clock.
Note: This input has an internal pullup.
28
B1, C1
RXDIN+,
RXDIN–
I
High-Speed
Differential
C9
D9
C10
D10
A9
B9
A10
B10
RXDOUT3+
RXDOUT3–
RXDOUT2+
RXDOUT2–
RXDOUT1+
RXDOUT1–
RXDOUT0+
RXDOUT0–
O
LVDS
Differential Parallel Receive Data Output.
The data recovered from the signal present on RXDIN
is demultiplexed and output as a 4-bit parallel word via
RXDOUT[3:0]. The bit order for demultiplexing is
selected by the RXMSBSEL input. The RXDOUT[3:0]
outputs are aligned to the rising edge of RXCLK1.
C3
RXLOL
O
LVTTL
Receiver Loss-of-Lock.
This output is asserted (driven low) when the recovered clock frequency deviates from the reference
clock by the amount specified in Table 5 on page 9.
Differential Receive Data Input.
The receive clock and data signals RXCLK1,
RXCLK2, and RXDOUT[3:0] are recovered from the
high-speed data signal present on these pins.
Rev. 1.5
Si5110
Pin
Number(s)
Name
I/O
Signal Level
D8
RXMSBSEL
I
LVTTL
Description
Receive Data Bus Bit Order Select.
This input determines the order of the received data
bits on the RXDOUT[3:0] output bus.
For RXMSBSEL = 0, the first data bit received is output on RXDOUT0 and following data bits are output
on RDOUT1 through RXDOUT3.
For RXMSBSEL = 1, the first data bit is output on
RXDOUT3 and following data bits are output on RXDOUT2 through RXDOUT0.
Note: This input has an internal pulldown.
A4
RXREXT
A5
RXSQLCH
Receiver External Bias Resistor.
This resistor is used by the receiver circuitry to establish bias currents within the device. This pin must be
connected to GND through a 3.09 k1resistor.
I
LVTTL
Receiver Data Squelch.
When this input is low, the data on RXDOUT[3:0] is
forced to a zero state. Set RXSQLCH high for normal
operation.
The RXSQLCH input is ignored when operating in
Diagnostic Loopback mode (DLBK = 0).
Note: This input has an internal pullup.
A3
SLICELVL
I
C6
SLICEMODE
I
Slicing Level Adjustment.
Applying an analog voltage to this pin allows adjustment of the slicing level applied to the input data eye.
Tying this input to VREF sets the slicing offset to 0.
LVTTL
Slice Level Adjustment Mode.
The SLICEMODE input is used to select the mode of
operation for slicing level adjustment. When SLICEMODE = 0, Absolute Slice mode is selected. When
SLICEMODE = 1, Proportional Slice mode is selected.
Note: This input has an internal pulldown.
K8
K7
TXCLK4IN+,
TXCLK4IN–
I
LVDS
Differential Transmit Data Clock Input.
The rising edge of this input clocks data present on
TXDIN into the device. TXCLK 4IN is also used as the
Si5100 reference clock when the REFSEL input is set
low.
K6
K5
TXCLK4OUT+,
TXCLK4OUT–
O
LVDS
Divided Down Transmit Clock Output.
This clock output is generated by dividing down the
high-speed output clock, TXCLKOUT, by a factor of 4.
It is intended for use in counter clocking schemes that
transfer data between the system framer and the
Si5110. (See REFSEL and REFRATE descriptions.)
Rev. 1.5
29
S i 5 11 0
Pin
Number(s)
Name
I/O
Signal Level
J8
TXCLKDSBL
I
LVTTL
Description
High-Speed Transmit Clock Disable.
When this input is high, the output driver for TXCLKOUT is disabled. In applications that do not require the
output data clock, the output clock driver should be
disabled to save power.
Note: This input has an internal pulldown.
E1
F1
TXCLKOUT+,
TXCLKOUT–
G9
H9
G10
H10
J9
K9
J10
K10
TXDIN3+,
TXDIN3–
TXDIN2+,
TXDIN2–
TXDIN1+,
TXDIN1–
TXDIN0+,
TXDIN0–
I
LVDS
Differential Parallel Transmit Data Input.
The 4-bit data word present on these pins is multiplexed into a high-speed serial stream and output on
TXDOUT. The bit order for transmit multiplexing is
selected by the TXMSBSEL input. The data on
TXDIN[3:0] is clocked into the device by the rising
edge of TXCLK4IN.
H1
J1
TXDOUT+,
TXDOUT–
O
CML
Differential High-Speed Transmit Data Output.
The 4-bit word input on TXDIN[3:0] is multiplexed into
a high-speed serial stream that is output on the TXDOUT pins. The bit order for transmit multiplexing is
selected by the TXMSBSEL input. The TXDOUT outputs are updated by the rising edge of TXCLKOUT.
K4
TXLOL
O
LVTTL
Transmit CMU Loss-of-Lock.
The TXLOL output is asserted (low) when the CMU is
not phase locked to the selected reference source or if
REFCLK is not present.
H4
TXMSBSEL
I
LVTTL
Transmit Data Bus Bit Order Select.
This input determines the order in which data bits
recovered on the TXDIN[3:0] bus are transmitted on
the high-speed serial output TXDOUT.
For TXMSBSEL = 0, data on TXDIN0 is transmitted
first followed by TXDIN1 through TXDIN3.
For TXMSBSEL = 1, TXDIN3 is transmitted first followed by TXDIN2 through TXDIN0.
High-Speed Transmit Clock Output.
The high-speed clock output, TXCLKOUT, is generated by the PLL in the transmit clock multiplier unit. Its
frequency is nominally 16 times or 32 times the
selected reference source.
Note: This input has an internal pulldown.
K3
30
TXREXT
Transmitter External Bias Resistor.
This resistor is used by the transmitter circuitry to
establish bias currents within the device. This pin must
be connected to GND through a 3.09 k1resistor.
Rev. 1.5
Si5110
Pin
Number(s)
Name
I/O
Signal Level
J6
TXSQLCH
I
LVTTL
Description
Transmit Data Squelch.
When TXSQLCH is set low, the output data stream on
TXDOUT is forced to a zero state. Set TXSQLCH high
for normal operation. The TXSQLCH input is ignored
when operating in Line Loopback mode (LLBK = 0).
Note: This input has an internal pullup.
D4–7, E4–6,
F4–6, G4–7
VDD
VDD
G2
VDDIO
VDDIO
B4
VREF
O
1.8 V
Supply Voltage.
Nominally 1.8 V.
1.8 V or 3.3 V LVTTL I/O Supply Voltage.
Connect to either 1.8 or 3.3 V. When connected to
3.3 V, LVTTL compatible voltage swings are supported on the LVTTL inputs and LVTTL outputs of the
device.
Voltage Ref
Voltage Reference.
The Si5110 provides an output voltage reference that
can be used by an external circuit to set the LOS
threshold, slicing level, or sampling phase adjustment.
The equivalent resistance between this pin and GND
should not be less than 10 k. The reference voltage
is nominally 1.25 V.
Rev. 1.5
31
S i 5 11 0
18. Ordering Guide
32
Part Number
Package
Temperature Range
Si5110-G-BC
99-Ball CBGA
(Prior Revision) RoHS-5
–20 to 85 °C
Si5110-H-BL
99-Ball PBGA
(Current Revision) RoHS-5
–20 to 85 °C
Si5110-H-GL
99-Ball PBGA
(Current Revision) RoHS-6
–20 to 85 °C
Rev. 1.5
Si5110
19. Package Outline
Figure 15 illustrates the package details for the Si5110. Table 9 lists the values for the dimensions shown in the
illustration.
Figure 15. 99-Ball Plastic Ball Grid Array (PBGA)
Table 9. Package Diagram Dimensions (mm)
Symbol
Min
Nom
Max
Symbol
Min
Nom
A
1.22
1.39
1.56
E1
9.00 BSC
A1
0.40
0.50
0.60
e
1.00 BSC
A2
0.32
0.36
0.40
S
0.50 BSC
A3
0.46
0.53
0.60
aaa
0.10
b
0.50
0.60
0.70
bbb
0.10
ccc
0.12
D
11.00 BSC
E
11.00 BSC
ddd
0.15
D1
9.00 BSC
eee
0.08
Max
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 JEDEC outline MO-192, variation AAC-1.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020C specification for Small Body Components.
Rev. 1.5
33
S i 5 11 0
20. 11x11 mm 99L PBGA Recommended PCB Layout
Symbol
Min
Nom
Max
X
0.40
0.45
0.50
C1
9.00
C2
9.00
E1
1.00
E2
1.00
Notes:
General
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing is per the ANSI Y14.5M-1994 specification.
3. 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 µm 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.
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-020C specification for Small Body Components.
34
Rev. 1.5
Si5110
DOCUMENT CHANGE LIST
Revision 1.3 to Revision 1.4

Revision 0.53 to Revision 1.0















Updated "18. Ordering Guide" on page 32.
Updated "19. Package Outline" on page 33.
 Updated "20. 11x11 mm 99L PBGA Recommended
PCB Layout" on page 34.

Update Si5110 1. "Detailed Block Diagram" on page
4 to clarify control RXAMPMON and CMU timing
sources.
Figure 1 on page 5; clarified the measurement of
VICM, and VOCM
Updated Table 2 on page 6.
Updated Table 3 on page 8.
Updated Table 4 on page 9.
Updated Table 5 on page 9.
Updated Table 6 on page 10.
Updated Table 7 on page 11.
Update 3. "Typical Application Schematic" on page
12 to show connection between FIFORSTb and
FIFOERRb.
Updated RXAMPMON description and equation in
5.2.1. "Receiver Signal Amplitude Monitoring" on
page 13.
Updated LOSLVL equations, and related figures
(Figure 4 and Figure 5 on page 16).
Clarified 5.3. "Clock and Data Recovery (CDR)" on
page 14.
Added Figure 9, “CML Output Driver Termination
(TXCLKOUT, TXDOUT),” on page 21 and Figure 10,
“Receiver Differential Input Circuitry,” on page 21.
Updated RXAMPMON, RXDIN, REFCLK, and
TXCLK4IN pin descriptions in 17. "Pin Descriptions:
Si5110" on page 25.
Updated 19. "Package Outline" on page 33.
Revision 1.4 to Revision 1.5

Updated Table 4, “AC Characteristics (TXCLK4OUT,
TXCLK4IN, TXCLKOUT, TXDIN, TXDOUT),” on
page 9.
Revision 1.0 to Revision 1.1


Updated Table 2, “DC Characteristics,” on page 6.
Updated Table 9, “Package Diagram Dimensions
(mm),” on page 33.
Revision 1.1 to Revision 1.2

Updated LVDS Input Impedance in Table 2, “DC
Characteristics,” on page 6.
 Added test condition for Acquisition Time in Table 6,
“AC Characteristics (Transmitter Clock Multiplier)1,”
on page 10.
 Updated 19. "Package Outline" on page 33.
Revision 1.2 to Revision 1.3


Updated chip graphic on page 1.
Corrected "18. Ordering Guide" on page 32.
Rev. 1.5
35
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