Integrated

Circuit

Systems, Inc.

General Description

Features

ICS9147-22

Block Diagram

9147-22 Rev A 072597P

Pin Configuration

48-Pin SSOP

Pentium is a trademark on Intel Corporation.

•

Generates system clocks for CPU, IOAPIC, SDRAM,

PCI, plus 14.318 MHz (REF0:1), USB, Super I/O

•

Supports single or dual processor systems

•

Supports Intel 60, 66.8MHz, Cyrix 55, 75MHz plus 83.3

and 68MHz (Turbo of 66.6) speeds.

•

Synchronous clocks skew matched to 250ps window on

CPU, SDRAM and 500ps window on PCI clocks

•

CPU clocks to PCI clocks skew 1-4ns (CPU early)

•

Two fixed outputs, 48MHz and 24 MHz

•

Separate 2.5V and 3.3V supply pins

- 2.5V or 3.3V output: CPU, IOAPIC

- 3.3Voutputs: SDRAM, PCI, REF, 48/24 MHz

•

No power supply sequence requirements

•

48pin300milSSOP

The ICS9147-22 is a Clock Synthesizer chip for Pentium

and PentiumPro plus Cyrix CPU based Desktop/Notebook

systems that will provide all necessary clock timing.

Features include four CPU, seven PCI and eight SDRAM

clocks. Two reference outputs are available equal to the

crystal frequency, plus the IOAPIC output powered by

VDDL. Additionally, the device meets the Pentium power-

up stabilization, which requires that CPU and PCI clocks

be stable within 2ms after power-up.

High drive PCICLK and SDRAM outputs typically provide

greater than 1 V/ns slew rate into 30pF loads. CPUCLK

outputs typically provide better than 1V/ns slew rate into

clock outputs typically provide better than 0.5V/ns slew

rates.

The ICS9147-22 accepts a 14.318MHz reference crystal

or clock as its input and runs on a 3.3V supply.

Power Groups

VDD1 = REF (0:1), X1, X2

VDD2 = PCICLK_F, PCICLK (0:5)

VDD3 = SDRAM (0:7),

VDD4 = 48MHz, 24MHz

VDDL = IOAPIC, CPUCLK (0:3)

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 information being relied upon by the

customer is current and accurate.