SY87721L

1

Micrel, Inc.

M9999-072705

hbwhelp@micrel.com or (408) 955-1690

CLOCK AND DATA RECOVERY WITH

INTEGRATED CLOCK MULTIPLIER UNIT

DESCRIPTION

FEATURES

SY87721L

s Recovers any data and clock from 28Mbps to

2.7Gbps

• OC-1, OC-3, OC-12, OC-48, ATM

• Gigabit Ethernet, Fast Ethernet

• Fibre Channel, 2x Fibre Channel

• P1394, Infiniband

• SMPTE-259, SMPTE-292

• Proprietary optical transport

s Integrated clock multiplier unit with low jitter

generation

s Complies with Bellcore, ITU/CCITT and ANSI

specifications

s Selectable mux for pass through; avoids jitter

accumulation when switching through backplanes

s Available in 64-Pin EPAD-TQFP package

The SY87721L is a complete Clock Recovery and Data

retiming integrated circuit for data rates from 28Mbps up to

2.7Gbps NRZ including SONET FEC data rates. Included

in the device, is a fully integrated Clock Multiplier Unit (CMU)

that is capable of generating frequencies that cover the

same data rate range as the CDR. The device is ideally

suited for SONET/SDH/ATM, Fibre Channel, and Gigabit

Ethernet applications, as well as other high-speed data

transmission applications.

Clock recovery and data retiming is performed by

synchronizing the on-chip VCO directly to the incoming data

stream. The VCO center frequency is controlled by the

reference clock frequency and the selected divide ratio.

On-chip clock generation is performed through the use of a

frequency multiplier PLL with a byte rate or code group rate

source as reference.

Rev.: B

Amendment: /0

Issue Date: July 2005

SIMPLIFIED BLOCK DIAGRAM

SY87721L

AnyRate

Data In

Reference

Clock

2

2

2

2

AnyRate

Data Out

Transmit

Clock

2

CDR

Recovered

Clock

CMU

APPLICATIONS

s SONET/SDH/ATM-based transmission systems,

modules, and test equipment

s Transponders and section repeaters

s Multiplexers: access, add drop (ADM), and terminal (TM)

s Terabit routers and broadband cross-connects

s Fiber optic test equipment

AnyRate is a registered trademark of Micrel, Inc.