Integrated

Circuit

Systems, Inc.

General Description

Features

ICS9159-05

9159-05 Rev F 9/29/98

Block Diagram

The ICS9159-05 is a low cost frequency generator designed

specifically for Pentium/Pentium Pro systems. The integrated

buffer minimizes skew and provides the early CPU clock required

by some chipsets such as the OPTi VIPER. A 14.318 MHz

XTAL oscillator provides the reference clock to generate

standard Pentium frequencies. The CPU clock makes gradual

frequency transitions without violating the PLL timing of

internal micro-processor clock multipliers.

The synchronous bus frequencies are selectable as CPU for

local bus or CPU/2 for PCI bus support. Green PC systems

are supported through power-down, doze, and glitch-free

stop clock modes.

•

Four CPU clocks operate up to 66.6 MHz at 3.3V with

glitch-free start and stop plus smooth transitions

•

3-6ns early CPU clock supports OPTi VIPER systems

•

Selection of 6 frequencies, tristate, or power-down

•

Six BUS clocks support local PCI bus operation

•

Skew window between synchronous outputs

•

Integrated buffer outputs drive up to 30pF loads

•

3.0V - 3.7V supply range

•

28-pin DIP or 28-pin 300-mil SOIC package

Pentium is a trademark of Intel Corporaton.

PowerPC is a trademark of Motorola Corporation.

Applications

•

Ideal for green Pentium/Pentium Pro and 486 PCI

systems such as Pentium, PowerPC

™ etc.

ICS reserves the right to make changes in the device data identified in this publication

without further notice. ICS advises its customers to obtain the latest version of all

device data to verify that any

28-Pin 300-mil SOIC

Pin Configuration