Micrel, Inc.

SM840001

March 2010

5

M9999-031810-B

Functional Description

The SM840001 provides a high performance and high

accuracy solution for a precision clock source at 106.25

or 212.50MHz derived from a low cost 26.5625MHz Xtal.

A single 12mA LVCMOS output is provided with tri state

capability, controlled via an external pin (OE).

The design of the SM840001 consumes very low power

in the PLL due to a patented technology in the VCO and

the associated dividers. The VCO range is ~3.2GHz to

3.5GHz providing high resolution and easy integer divide

ratios. Output Divider ratios are fixed at either ÷15 or ÷30

controlled via the FSEL pin, and the feedback divider

also fixed at ÷120. Duty Cycle is inherently improved and

guarantees tight control and stability on this critical

specification. The provides improved specifications for

Duty Cycle, Jitter, Phase Noise, Power Consumption,

and noise sensitivity. Additionally, the SM840001 will

operate at either 3.3V or 2.5V supplies.

Switching Waveforms

RMS Phase Noise/Jitter

Phase Noise Plot: 106.25MHz @ 3.3V

Phase Noise Plot: 212.5MHz @ 3.3V