Integrated

Circuit

Systems, Inc.

General Description

Features

ICS9147-12

Block Diagram

9147-12 Rev A 072597P

Pin Configuration

48-Pin SSOP

Pentium is a trademark on Intel Corporation.

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Generates system clocks for CPU, IOAPIC, SDRAM,

PCI, plus 14.318 MHz REF(0:2), USB, Plus Super I/O

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Supports single or dual processor systems

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

and 68MHz (Turbo of 66.6) speeds.

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Synchronous clocks skew matched to 250ps window on

CPU, SDRAM and 500ps window on PCI clocks

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

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Two fixed outputs, 48MHz and 24 MHz

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Separate 2.5V and 3.3V supply pins

- 2.5V or 3.3V output: CPU, IOAPIC

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

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No power supply sequence requirements

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48pin300milSSOP

The ICS9147-12 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. Three reference outputs are available equal to the

crystal frequency, plus the IOAPIC output powered byVDDL.

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

typically provide better than 1V/ns slew rate into 20pF loads

typically provide better than 0.5V/ns slew rates.

The ICS9147-12 accepts a 14.318MHz reference crystal or

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

Power Groups

VDD1=REF(0:2),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.