19-2709; Rev 3; 2/07
Multirate Clock and Data Recovery
with Limiting Amplifier
MAX3872
General Description
Features
♦ Multirate Data Input: 2.667Gbps (FEC), 2.488Gbps,
1.244Gbps, 622.08Mbps, 155.52Mbps,
1.25Gbps/2.5Gbps (Ethernet)
The MAX3872 is a compact, multirate clock and data
recovery with limiting amplifier for OC-3, OC-12, OC-24,
OC-48, OC-48 with FEC SONET/SDH and Gigabit
Ethernet (1.25Gbps/2.5Gbps) applications. Without using
an external reference clock, the fully integrated phase-
locked loop (PLL) recovers a synchronous clock signal
from the serial NRZ data input. The input data is then
retimed by the recovered clock, providing a clean data
output. An additional serial input (SLBI ) is available for
system loopback diagnostic testing. Alternatively, this
input can be connected to a reference clock to maintain a
valid clock output in the absence of data transitions. The
device also includes a loss-of-lock (LOL) output.
♦ Reference Clock Not Required for Data
Acquisition
♦ Exceeds ANSI, ITU, and Bellcore SONET/SDH
Jitter Specifications
♦ 2.7mUI
Jitter Generation
RMS
♦ 10mV
Input Sensitivity Without Threshold
P-P
Adjust
♦ 0.65UI
High-Frequency Jitter Tolerance
170mV Input Threshold Adjust Range
♦ Clock Holdover Capability Using Frequency-
P-P
♦
The MAX3872 contains a vertical threshold control to
compensate for optical noise due to EDFAs in DWDM
transmission systems. The recovered data and clock
outputs are CML with on-chip 50Ω back termination on
each line. Its jitter performance exceeds all
SONET/SDH specifications.
Selectable Reference Clock
♦ Serial Loopback Input Available for System
Diagnostic Testing
♦ Loss-of-Lock (LOL) Indicator
The MAX3872 operates from a single +3.3V supply and
typically consumes 580mW. It is available in a 5mm x
5mm 32-pin thin QFN with exposed-pad package and
operates over a -40°C to +85°C temperature range.
Applications
Ordering Information
SONET/SDH Receivers and Regenerators
PKG
CODE
PART
TEMP RANGE PIN-PACKAGE
Add/Drop Multiplexers
MAX3872EGJ
-40°C to +85°C 32 QFN-EP*
G3255-1
T3255-3
Digital Cross-Connects
MAX3872ETJ+ -40°C to +85°C 32 TQFN-EP*
SONET/SDH Test Equipment
DWDM Transmission Systems
Access Networks
*EP = Exposed pad.
+Denotes lead-free package.
Pin Configuration appears at end of data sheet.
Typical Application Circuit
+3.3V
+3.3V
CAZ
0.1μF
C
+3.3V +3.3V
FIL
0.82μF
V
CC
FIL VCC_VCO CAZ- CAZ+ FREFSET V
CC
FILTER
OUT+
OUT-
SDI+
MAX3745
SDO+
SDO-
SDI-
CML
CML
IN
SLBI+
SLBI-
MAX3872
GND
SCLKO+
SCLKO-
+3.3V
V
V
CTRL
REF
SYSTEM
LOOPBACK DATA
SIS LREF LOL RS1 RS2 RATESET GND
+3.3V
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.