Integrated
Circuit
Systems, Inc.
Product Brief
M844
M
ULTI
-R
ATE
C
LOCK
R
ECOVERY
G
ENERAL
D
ESCRIPTION
The M844 Multi-Rate Clock Recovery module provides
low jitter clock recovery from NRZ or RZ input data
formats. Four data rates are digitally selectable: 9.953,
10.3125, 10.664, or 10.709Gb/s. Incoming data is first
amplified by a limiting amplifier. The data is then both:
a) provided as the module’s unretimed data output, and
b) applied to the clock recovery circuitry. A Phase
Locked Loop (PLL) incorporates frequency multipliers
and a SAW-based Voltage Control SAW Oscillator
(VCSO) to minimize clock jitter. The VCSO provides the
high Q, low noise, and high stability needed for the
narrow bandwidth PLL operation. Micro-strip bandpass
filters are used to produce sinusodal clock output with
low harmonic and sub-harmonic distortion.
P
IN
A
SSIGNMENT
(1.575 x 3.2 inch SMA)
DATA_IN
M844
Din
CONT 2
CONT 1
ALM
GND
GND
VEE -5V
VCC +5V
1/4Cout
Cout
Dout
1/4 CLK_OUT
F
EATURES
•
4 selectable NRZ or RZ rates: 9.953, 10.3125,
•
•
•
•
•
•
•
•
10.664, or 10.709Gb/s
Superior VCSO-based PLL jitter performance 0.12 ps
peak-to-peak max
0.02ps rms jitter, typical (12kHz-20MHz)
Low phase noise -85dBc/Hz @ 1kHz offset
6mV peak-to-peak input sensitivity
Up to 700mV peak-to-peak un-retimed NRZ or RZ
data output
+5V and -5V power supplies
Designed for high-speed fiber optic applications
Easy to connect 1.575 x 3.2 inch SMA package
Example Input/Output Frequency Combinations
Operating
Data Rate
(Gb/s)
9.9530
10.3125
10.6640
10.7090
Clock Output Freq
(GHz)
OC-192
OC-48
9.9530
2.488
10.3125
2.577
10.6640
2.666
10.7090
2.677
Application
DATA_OUT
CLK_OUT
OC-192
B
LOCK
D
IAGRAM
M844
DATA_IN
Lim
Amp
RF
Amp
2x
Frequency
Multiplier
DATA_OUT
RF
Amp
4x
Frequency
Multiplier
RF
Amp
Pwr
Div
Phase Detector
Op-
Amp
CLK_OUT
SAW Delay Lines 1 - 4
2x
Frequency
Multiplier
Pwr
Div
RF
Amp
SP4T
SW
SP4T
SW
RF
Amp
Pwr
Div
1/4CLK_OUT
Rate
Select
Phase
Shifter
M844 Rev 1.3
M844 Multi-Rate Clock Recovery
Revision 12Nov2003
●
Integrated Circuit Systems, Inc.
Communications Modules
●
w w w. i c s t . c o m
●
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