T
R
I Q
U
I
N
T
S E M I C O N D U C T O R , I N C .
TELECOM
PRODUCTS
1
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The TQ8103 is a monolithic clock and data recovery (CDR) IC that receives
NRZ data, extracts the high-speed clock, and presents the separated data
and clock as its outputs. This device is designed specifically for SONET
OC-12 and SDH STM-4 applications at 622 Mb/s.
Its on-chip phase-locked loop (PLL) generates a stable 622.08 Mb/s
reference based upon an external 38.88 MHz TTL reference. The PLL is
based on a VCO constructed from integrated reactive components, which
form a low-jitter, high-Q differential tank circuit. Both frequency- and
phase-detect circuits reliably acquire and hold lock in worst-case SONET
jitter conditions and scrambling patterns. The lock-detect circuitry signals
when the CDR acquires frequency lock.
Typical SONET/SDH system applications for the TQ8103 include:
Transmission system transport cards
Switch and cross-connect line cards
ATM physical layer interfaces
Test equipment
Add/drop multiplexers
Figure 1. Typical Application
TQ8103
622 Mb/s Clock
& Data Recovery
Features
Single-chip CDR circuit for
622 Mb/s data
Exceeds Bellcore and ITU jitter
tolerance maps
Single-ended ECL input has loop-
through path for external 50 ohm
termination to minimize stubs
and reflections
Clock and data outputs are
differential ECL
Provides complete high-speed
OC-12/STM-4 solution when
used with TQ8101 or TQ8105
Mux/Demux/Framer/PLL
External loop filter requires
simple passive network
Maintains clock in absence of data
28-pin leaded chip carrier
Can be used with a high-speed
external clock
OUCHP
LOCK
CKREF
V
CTL
D
OUTP
SINI
SINO
XTCKI
SELCK
SEL
V
REF
CK
OUTP
CK
OUTN
V
TT
ECL data in
(single-ended)
38.88-MHz TTL
clock oscillator
20K
62
1 mF
50
V
TT
10K
1000 pF
V
TT
D
OUTN
50
50
1000 pF
TQ8103
2
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Figure 2. TQ8103 Block Diagram
Functional Description
The TQ8103 CDR integrates separate detectors for
acquiring frequency lock and maintaining precise phase
lock. When the CDR is locked onto an incoming NRZ
data stream, its phase-detect circuitry compares the
phase of the incoming NRZ data and the phase of the
generated 622.08 MHz clock. When they differ, the
resulting error signal nulls the phase difference and
puts the generated 622.08 MHz clock back in phase
with the incoming data. In this mode, the LOCK output
is high.
The phase-detect circuit operates only when the
incoming NRZ data transitions between states. SONET
and SDH employ scrambling, which provides an
average transition density of 50 percent; however, some
data patterns can generate legitimate scrambled signals
with a significant number of consecutive ones or zeros.
The TQ8103 maintains lock over bit sequences of over
100 consecutive zeros or ones.
When the input data is lost or too many bit times occur
without a transition, the PLL (which generates the
622.08 MHz clock) eventually drifts. The lock-detect
circuit constantly compares the generated 622.08 MHz
clock (divided by 16) and the external 38.88 MHz
reference. When the PLL drifts more than 2000 PPM
from the reference, the LOCK output goes low.
The SEL input selects between the phase-detect and
frequency-detect circuits. When the PLL drifts out of
lock, taking SEL low reverses the drift by switching in
the frequency-detect circuit. Connecting the LOCK
output directly to the SEL input should ensure that
frequency lock is maintained in the absence of data.
It is recommended, however, that a low-pass filter be
added between LOCK and SEL to allow for orderly
transitions between these circuits. Once the PLL
frequency is within 500 PPM of the reference, the LOCK
output returns high. As the SEL input goes high, the
phase-detect circuit again maintains lock to the
incoming NRZ data.
The TQ8103 can also be used as a standalone 622.08 MHz
frequency reference. When SEL is held low, the PLL
utilizes only the frequency-detect circuit. The PLL locks
onto the external 38.88 MHz reference to generate the
desired 622.08 MHz output.
Frequency
Detect
Charge
Pump
VCO
CKREF
OUCHP
V
CTL
D
OUTP
LOCK
SINI
SINO
XTCKI
SELCK
Phase
Detect
D Q
+16
Loc k
Detect
Mux
SEL
V
REF
V
EE
V
DD
D
OUTN
CK
OUTP
CK
OUTN
TQ8103
TELECOM
PRODUCTS
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3
Application Information
Loop Filter Design
The TQ8103 requires an external loop filter. Care should
be taken in the implementation of the filter. Good high-
frequency design techniques should be used, with the
loop filter being connected into the analog ground. The
analog supply should be well filtered.
Data Input Considerations
The serial data input line is a high-frequency ECL signal,
and should be kept in a 50 ohm controlled impedance
environment. Reflections on the serial input are
minimized through the use of a separate loopback
termination pin, SINO. A 50 ohm chip resistor between
SINO and V
TT
minimizes stub length for the best signal
quality. Another physical design consideration is to
place the TQ8103 and its companion high-speed ICs as
close as possible to the optics while observing good
analog design practice on supply filtering and
grounding.
External Frequency Reference
The externally supplied 38.88 MHz CKREF input needs
to have low jitter with fast rise and fall times. Typical
applications will use a telecom crystal oscillator such as
the Connor-Winfield S14R6-38.88. SONET requires freq-
uency sources to be accurate to
20 ppm over temper-
ature, voltage, and aging. The CKREF input is a reference
frequency for initial frequency lock and for the lock-detect
circuit, so it can tolerate accuracies of up to
100 ppm.
Jitter Tolerance
Jitter tolerance describes the ability of the CDR circuit
to track timing variations (jitter) in the received signal.
The Bellcore and ITU specifications allow the received
optical signal to contain jitter. The amount of jitter that
must be tolerated is a function of the frequency content
of the jitter. The CDR must tolerate many unit intervals
(bit times) of low-frequency jitter, but is not asked to
tolerate large amounts of jitter at higher frequency. The
performance shown in the "Typical Performance Data"
section shows that the TQ8103 offers a wide margin
over the specification limits.
Jitter tolerance is a system-level issue that is directly
affected by the quality of the optics, the quality of the
layout (and decoupling), and the specific
implementation of the loop filter. The recommended
loop filter, described above, has been chosen to provide
a robust margin on jitter tolerance.
Figure 3. External Loop Filter
OUCHP
V
CTL
1 mF
62
20 K
1000 pF
TQ8103
2
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Figure 4. TQ8103 Pinout
Table 1. Signal Descriptions
Pin
Signal
Type
Description
1
V
DDA
Supply
Analog ground for VCO
2
V
EEA
Supply
Analog 5V supply for VCO
3
V
CTL
Analog In
VCO control voltage input; connect to loop filter
4
OUCHP
Analog Out
Charge pump output; connect to loop filter
5
V
DD
Supply
Ground (0V)
6
V
DD
Supply
Ground (0V)
7
SINI
ECL In
Serial data input
8
SINO
ECL Term
Loopback of SINI for termination of serial data input; connect with 50
to V
TT
9
V
EE
Supply
5V supply
10
V
REF
Analog
Optional reference voltage for single-ended ECL input
11
V
EE
Supply
5V supply
12
D
OUTN
ECL Out
Differential data output, complement
13
D
OUTP
ECL Out
Differential data output, true
14
CK
OUTN
ECL Out
Differential clock output, complement
(Continued on next page)
2 5 V
CC
2 4 SEL
2 3 LOCK
2 2 SELCK
2 1 XTCKI
2 0 V
EE
1 9 V
CC
D
OU
T
N
12
D
OU
T
P
13
CK
R
E
F
17
V
DD
18
SINI
7
SINO
8
V
E E
11
4
OUCHP
3
V
CTL
2
V
EEA
1
V
DDA
2
8
V
EE
2
6
V
DD
TQ8103
CDR
2
7
V
CC
CK
OU
T
P
15
CK
OU
T
N
14
V
R E F
10
V
E E
9
V
D D
6
V
D D
5
V
DD
16
TQ8103
TELECOM
PRODUCTS
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5
Table 3. Power Consumption
Parameter
Symbol
Minimum
Nominal
Maximum
Unit
Positive supply current
I
CC
5
mA
Negative supply current
I
EE
210
mA
Thermal impedance
JA
4 0
C/W
Note:
These values supersede the recommended operating conditions (Table 2) unless otherwise noted.
Table 2. Recommended Operating Conditions
Parameter
Symbol
Minimum
Nominal
Maximum
Unit
Positive supply
V
CC
4.5
5
5.5
V
Negative supply
V
EE
5.5
5
4.75
V
Termination voltage
V
TT
1.9
2.0
2.1
V
Operating ambient temperature
T
A
0
8 5
C
Table 1. Signal Descriptions (continued)
Pin
Signal
Type
Description
Specifications
15
CK
OUTP
ECL Out
Differential clock output, true
16
V
DD
Supply
Ground (0V)
17
CKREF
TTL In
Reference clock input for frequency detect and lock detect
18
V
DD
Supply
Ground (0V)
19
V
CC
Supply
+5V supply
20
V
EE
Supply
5V supply
21
XTCKI
ECL In
External clock input; selected using SELCK
22
SELCK
TTL In
External clock select: low = internal VCO, high = XTCLK
23
LOCK
TTL Out
Lock-detect output
24
SEL
TTL In
Detection circuit select; low = frequency-detect, high = phase-detect
25
V
CC
Supply
+5V supply
26
V
DD
Supply
Ground (0V)
27
V
CC
Supply
+5V supply
28
V
EE
Supply
5V supply
TQ8103
2
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Table 4. DC Characteristics--ECL I/O
(1)
Parameter
Condition
Symbol
Minimum
Nominal
Maximum
Unit
Internal ECL reference
(2)
V
REF
1300
mV
Input HIGH voltage
(3)
V
IH
1100
700
mV
Input LOW voltage
(3, 4)
V
IL
V
TT
1500
mV
Output HIGH voltage
(5)
V
OH
1000
0
700
mV
Output LOW voltage
(5)
V
OL
V
TT
1600
mV
Input HIGH current
(6)
I
IH
10
A
Table 6. AC Characteristics
(1)
Parameter
Condition
Symbol
Minimum
Nominal
Maximum
Unit
Clock to data time
Figure 5
t
O
100
350
ps
Data output rise/fall times
(7)
t
R
, t
F
350
ps
Clock output rise/fall times
(7)
t
R
, t
F
300
ps
TTL output rise/fall times
(8)
t
R
, t
F
5
ns
Acquire time
(9)
3
ms
Notes (Tables 4, 5, and 6):
1. Applies over recommended operating range
2. Single-ended inputs, V
EE
= 5V
3. V
REF
= 1300 mV
4. V
TT
= 2.0V
5. R
LOAD
= 50 ohms to V
TT
= 2.0V
6. Not tested; consistent with V
OH
and V
OL
tests
7. 50 ohm load, 20% to 80% levels
8. 20 pF load, 0.8V to 2.0V
9. With recommended loop filter
Table 5. DC Characteristics--TTL I/O
(1)
Parameter
Condition
Symbol
Minimum
Nominal
Maximum
Unit
Input HIGH voltage
V
IH
2.0
V
CC
V
Input LOW voltage
V
IL
0
0.8
V
Input HIGH current
V
IH(MAX)
I
IH
100
A
Input LOW current
V
IL(MIN)
I
IL
100
A
Output HIGH voltage
I
OH
= 3 mA
V
OH
2.4
V
CC
V
Output LOW voltage
I
OL
= 1 mA
V
OL
0
0.4
V
Input capacitance
(6)
C
IN
8
pF
Output capacitance
(6)
C
OUT
10
pF
D
OUT
t
O
CK
OUT
Figure 5. Clock-to-Data Timing
TQ8103
TELECOM
PRODUCTS
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7
Table 7. Absolute Maximum Ratings
Parameter
Symbol
Minimum
Nominal
Maximum
Unit
Positive supply
V
CC
0
7
V
Negative supply
V
EE
7
0
V
Output voltage
V
O
ECL
V
EE
0.5
+0.5
V
Output current
I
O
ECL
--
40
mA
Input voltage
V
I
ECL
V
EE
0.5
+0.5
V
Input current
I
I
ECL
1
1
mA
Output voltage
V
O
TTL
0.5
V
CC
+ 0.5
V
Output current
I
O
TTL
20
mA
Input voltage
V
I
TTL
0.5
V
CC
+ 0.5
V
Input current
I
I
TTL
1
1
mA
Junction temperature
T
J
55
+150
C
Storage temperature
T
S
65
+175
C
Power dissipation
P
D
2
W
Notes:
If the device is subjected to the listed conditions, its reliability may be impaired.
Beyond the listed conditions, the safety of the device cannot be guaranteed.
TQ8103
2
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Typical Performance Data
Figure 6. Jitter Tolerance
Table 8. Typical Performance Data
Waveforms
2012
PRBS data pattern
2
23
RMS jitter
7.855 ps
Peak-to-peak jitter
55 ps
Figure 7. Output Eye Diagram with extracted clock
0
0.5
1
1.5
2
2.5
3
3.5
4
10
100
1000
10000
Frequency (KHz)
Jitter Tolerance, unit intervals
TQ8103 Jitter Tolerance
Bellcore Limit
TQ8103
TELECOM
PRODUCTS
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9
The information provided herein is believed to be reliable; TriQuint assumes no liability for inaccuracies or
omissions. TriQuint assumes no responsibility for the use of this information, and all such information
shall be entirely at the user's own risk. Prices and specifications are subject to change without notice.
No patent rights or licenses to any of the circuits described herein are implied or granted to any third party.
TriQuint does not authorize or warrant any TriQuint product for use in life-support devices and/or systems.
Copyright 1997 TriQuint Semiconductor, Inc. All rights reserved.
Revision 1.1.A
November 1997
Ordering Information
TQ8103-Q
622 Mb/s Clock & Data Recovery IC in 28-pin MQuad Package
ETF-8103
Evaluation Board
Additional Information
For latest specifications, additional product information,
worldwide sales and distribution locations, and information about TriQuint:
Web: www.triquint.com
Tel: (503) 615-9000
Email: sales@tqs.com
Fax: (503) 615-8900
For technical questions and additional information on specific applications:
Email: applications@tqs.com
Mechanical Specifications
Figure 8. TQ8103 Package Dimensions
.028
.018
.410
.015
.040 MIN.
.172
.005
.104
.005
.060
.490
.005
.445
.005
.490
.005
.445
.005
.050 TYP .
NON-A CCUM.
1
8
22
15
.045
X 45
.015
X 45
(3 PLCS)
.125
VENT PLUG