ICS343

MDS 343 F

1

Revision 090704

Integrated Circuit Systems, Inc.

Field Programmable Triple Output SS VersaClock Synthesizer

Description

The ICS343 is a low cost, triple-output, field program-

mable clock synthesizer. The ICS343 can generate

three output frequencies from 250 kHz to 200 MHz,

using up to three independently configurable PLLs.

The outputs may employ Spread Spectrum techniques

to reduce system electro-magnetic interference (EMI).

Using ICS’ VersaClock™ software to configure the PLL

and output, the ICS343 contains a One-Time Program-

mable (OTP) ROM to allow field programmability. Using

Phase-Locked Loop (PLL) techniques, the device runs

from a standard fundamental mode, inexpensive crys-

tal, or clock. It can replace multiple crystals and oscilla-

tors, 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 ICS343 is also available in factory-programmed

custom versions for high-volume applications.

Features

power CMOS process

clocks, see the ICS342. 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

VDD

GND

CLK1

CLK3

CLK2

PLL Clock Synthesis,

Spred Spectrum and

Control Circuitry

X2

Crystal or

clock input

External capacitors are

required with a crystal input.

X1/ICLK