ICS342

MDS 342 F

1

Revision 090704

Integrated Circuit Systems, Inc.

Field Programmable Dual Output SS VersaClock Synthesizer

Description

The ICS342 is a low cost, dual-output, field

programmable clock synthesizer. The ICS342 can

generate two output frequencies from 250 kHz to 200

MHz, using up to two independently configurable PLLs.

The outputs may employ Spread Spectrum techniques

to reduce system electro-magnetic interference (EMI).

PLL and output, the ICS342 contains a One-Time

Programmable (OTP) ROM to allow field

programmability. Programming features include 2

selectable configuration registers. Using Phase-Locked

Loop (PLL) techniques, the device runs from a

standard fundamental mode, inexpensive crystal, or

clock. It can replace multiple crystals and oscillators,

saving board space and cost.

The device also has a power down feature that

tri-states the clock outputs and turns off the PLLs when

the PDTS pin is taken low.

The ICS342 is also available in factory programmed

custom versions for high-volume applications.

Features

selection

output clocks, see the ICS343. For more than three

outputs, see the ICS345 or ICS348.

Block Diagram

Crystal

Oscillator

PDTS (both outputs and PLL)

OTP ROM

with PLL

Divider

Values

SEL

VDD

GND

CLK1

CLK2

PLL Clock Synthesis,

Spred Spectrum and

Control Circuitry

X2

Crystal or

clock input

External capacitors are

required with a crystal input.

X1/ICLK