Integrated

Circuit

Systems, Inc.

General Description

Features

ICS9248-73

Block Diagram

Pentium II is a trademark of Intel Corporation

I

Frequency Timing Generator for Pentium II Systems

9248-73 Rev B 2/10/00

Pin Configuration

•

Generates the following system clocks:

- 2 - CPUs @ 2.5V , up to 150MHz.

- 1 - IOAPIC @ 2.5V, PCI/2MHz.

- 9 - SDRAMs @ 3.3V, up to 150MHz.

-2-3V66@3.3V,2xPCIMHz.

- 8 - PCIs @ 3.3V.

- 2 - 48MHz, @ 3.3V fixed.

-1-REF@3.3V,14.318MHz.

- 1 - 24_48MHz, @ 3.3V fixed.

•

Supports spread spectrum modulation ,

down spread 0 to -0.5%, ±0.25% center spread.

•

Efficient power management scheme through PD#

•

Uses external 14.138 MHz crystal

48-Pin 300 mil SSOP

The ICS9248-73 is a single chip clock for Intel Pentium II.

It provides all necessary clock signals for such a system.

Spread spectrum typically reduces EMI by 8dB to 10 dB.

This simplifies EMI qualification without resorting to board

design iterations or costly shielding. The ICS9248-73

employs a proprietary closed loop design, which tightly

controls the percentage of spreading over process and

temperature variations.

Power Groups

GNDREF,VDDREF =REF&Crystal

GND3V66,VDD3V66 =3V66

GNDPCI,VDDPCI=PCICLK

GNDCOR,VDDCOR=PLLcore

GND48,VDD48 =48MHz

GNDSDR,VDDSDR=SDRAM

GNDLCPU,VDDLCPU=CPUCLK

GNDAPIC,VDDAPIC=IOAPIC

*120K ohm pull-up to VDD on indicated inputs.

**60K ohm pull-up to VDD on indicated inputs.

1. These pins will have 2x drive strength

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.