SM840051

10 Gigabit Ethernet Ultra-Low Jitter Clock

Synthesizer

RotaryWave is a trademark of Multigig, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (

May 2010

M9999-050710-C

General Description

The SM840051 clock synthesizer was designed for

Ethernet standards. The SM840051 is optimized for 77.76,

78.125, 80.56, 155.52, 156.25, and 161.13MHz, using a

crystal at 1/8th the output frequency. The SM840051

includes a unique power reduction methodology, along

with a patented RotaryWave™ architecture, that provides

a stable clock with very low noise for optimized

performance. This yields an overall improved Bit Error

Rate (BER) and improved waveform integrity.

Power supplies of either 3.3V or 2.5V are supported, with

superior jitter and phase noise performance. An FSEL pin

supports 4x or 8x multiplication of the crystal frequency.

The SM840051 provides ultra-low jitter, and consumes low

power.

Datasheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

• Generates a single LVCMOS/LVTTL output

• Output Frequencies: 77.76, 78.125, 80.56, 155.52,

156.25, and 161.13MHz

• RMS Phase Jitter at 156.25MHz( 1.875MHz-20MHz):

58fs (typical)

• Integrated loop filter components

• Operates with either a 3.3V or 2.5V supply

• Power consumption is <77mA @ 3.3 V

• Fundamental parallel resonant crystal

• Crystal Frequencies: 20.141601MHz,19.53125MHz, and

19.44MHz

• Industrial temperature range: –40°C to +75°C

• Available in 8-pin TSSOP package

Applications

• 10 Gigabit Ethernet

• SONET/SDH

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