Multirate Clock and Data Recovery with Limiting Amplifier

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 (active-low LOL) output.

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.

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

* Access Networks * Add/Drop Multiplexers * Digital Cross-Connects * DWDM Transmission Systems * SONET/SDH Receivers and Regenerators * SONET/SDH Test Equipment

* Multirate Data Input: 2.667Gbps (FEC), 2.488Gbps, 1.244Gbps, 622.08Mbps, 155.52Mbps, 1.25Gbps/2.5Gbps (Ethernet)

* Reference Clock Not Required for Data Acquisition

* Exceeds ANSI, ITU, and Bellcore SONET/SDH Jitter Specifications

* 2.7mUIRMS Jitter Generation

* 10mVP-P Input Sensitivity Without Threshold Adjust

* 0.65UIP-P High-Frequency Jitter Tolerance

* ±170mV Input Threshold Adjust Range

* Clock Holdover Capability Using Frequency-Selectable Reference Clock

* Serial Loopback Input Available for System Diagnostic Testing

* Loss-of-Lock (Active-Low LOL) Indicator