Integrated

Circuit

Systems, Inc.

General Description

Features

ICS9250-10

PRODUCT PREVIEW documents contain information on new

products in the sampling or preproduction phase of development.

Characteristic data and other specifications are subject to change

without notice.

Preliminary Product Preview

Block Diagram

Pentium II is a trademark of Intel Corporation

I

Frequency Timing Generator for Pentium II Systems

9250-10 Rev J 6/15/99

Pin Configuration

•

Generates the following system clocks:

- 3 CPU (2.5V) 66.6/100 MHz (up to 133MHz through

- 9 SDRAM (3.3V) up to 133MHz

- 8PCI(3.3V)@33.3MHz

-2IOAPIC(2.5V)@16.67or33.3MHz

- 2 Hublink clocks (3.3 V) @ 66.6 MHz

- 2 USB (3.3V) @ 48 MHz ( Non spread spectrum)

- 1REF(3.3V)@14.318MHz

•

Supports spread spectrum modulation ,

down spread 0 to -0.5%

•

Efficient power management scheme through PD#

•

Uses external 14.138 MHz crystal

56-Pin 300 mil SSOP

The ICS9250-10 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 ICS9250-10

employs a proprietary closed loop design, which tightly

controls the percentage of spreading over process and

temperature variations.

Power Groups

VDD0, GND0 =REF & Crystal

VDD1,GND1=3V66[1:0]

VDD2,GND2=PCICLK[7:0]

VDD3,GND3=PLLcore

VDD4,GND4= 48MHz[1:0]

VDD5,GND5 =SDRAM_F,SDRAM[7:0]

VDDL0,GNDL0=CPUCLK[2:0]

VDDL1,GNDL1=IOAPIC[1:0]

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