SY87729L
3.3V AnyClock®, 10MHz to 365MHz
Fractional N Synthesizer
AnyClock and AnyRate are registered trademarks of Micrel, Inc.
MicroWire is a trademark of National Semiconductor
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
General Description
The SY87729L is a complete rate independent frequency
synthesizer integrated circuit. From a single reference
source, this device generates a differential PECL
reference frequency for Micrel's SY87721L 10Mbps to
2.7Gbps combined CDR and CMU.
The SY87729L generates an exactly correct reference
frequency for common data transport protocols. This is
especially important in transponder applications, where a
standards compliant protocol data unit must be generated
downstream, even in the absence of any signal from the
associated upstream interface.
In addition, SY87729L will generate exactly correct
reference frequencies for common data transport protocols
augmented by forward error correction codes.
For proprietary applications, the SY87729L generates
reference frequencies guaranteed to enable the SY87721L
CDR to lock to any possible baud rate in its range.
SY87729L accepts configuration via a MicroWire™
interface.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
AnyClock®
Features
• Fractional synthesizer from 10MHz to 365MHz from a
single 27MHz reference oscillator
• Generates exactly the correct frequency for common
transport protocols with or without FEC
• Directly enables SY87721L to lock onto any data rate
within its range
• Exceeds BellCore and ITU jitter generation
specifications
• Programmable via MicroWire™ interface
• Available in 32-Pin EPAD-TQFP package
Applications
• Metro access system
• Transponders
• Multiplexers: access, add drop mux
• SONET/SDH/ATM-based transmission systems,
modules and test equipment
• Broadband cross-connects
• Fiber optic test equipment
• Protocols supported:
− OC-1, OC-3, OC-12, OC-48, ATM, Gigabit Ethernet,
Fast Ethernet, Fibre Channel, 2X Fibre Channel,
1394, InfiniBand, Proprietary Optical Transport
July 2011 M9999-072111-G
hbwhelp@micrel.com
or (408) 955-1690
