Integrated

Circuit

Systems, Inc.

General Description

Features

ICS9133X

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.

The ICS9133Xis designed to generate clocks for all 286, 386,

486, Pentium and RISC-based motherboards, including lap-

tops and notebook computers. The only external components

required are a 32.768 kHz crystal and decoupling capacitors.

The device generates the 14.318 MHz system clock, eliminating

the need for a 14.318 MHz crystal. High performance applications

may require high speed clock termination components. The

chip includes three independent clock generators plus the

32.768 kHz reference clock to produce all necessary frequencies,

including real time clock/DRAM refresh, master clock, CPU

clock, twice CPUclock frequency, keyboard clock, floppy

disk controller clock, serial communications clock and bus

clocks. Different frequencies from clock #2 can be selected

using the frequency select pins, but clock #1 will be at 14.318

MHz for all standard versions.

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Single 32.768 kHz crystal generates all PC

motherboard clocks

•

Cost-reduced version of popular ICS9132

•

Contains internal crystal load capacitors and

feedback bias

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3 independent clock generators

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Generates CPU clocks from 12.5 to 100 MHz

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Up to 7 output clocks

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Separate VDD for 32 kHz clock

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Output enable tristates outputs

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Power-down options available

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Operates from 3.3V or 5.0V supply

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Operates up to 66 MHz at 3.3V

•

Skew controlled 1X and 2X CPU clocks

•

20-pin PDIP or SOIC package

9133X Rev A 052897P

Block Diagram

32 kHz Motherboard Frequency Generator

VDD32 Supply

The ICS9133X has a separate power supply for the 32.768

kHz oscillator circuitry. This allows the 32 kHz clock to run

from a battery or other source while the main power to the

chip is disconnected. The VDD32 supply is guaranteed to

operate down to +2.0V, with the clock consuming less than

10µA at +3.3V with the main VDD at 0V.

The frequencies and power-down options in the ICS9133X

are mask programmable. Customer specific masks can be

made and prototypes delivered within 6-8 weeks from receipt

of order. Integrated Circuit Systems also offers standard versions,

such as that described in this data sheet.

Applications

Notebook/Palmtop Computers: The ICS9133X works with

+3V and +5V and a single 32.768 kHz crystal, making it the

ideal solution for generating clocks in portables with minimum

board space. The user can save power by using this single part

instead of oscillators or other frequency generators. The

ICS9133Xfurther reduces the current consumption by having

the ability to completely shut down the individual clocks

when not in use, while still maintaining the separately powered

32.768 kHz clock.