ICS9133X Datasheet, PDF (1/8 Pages) Integrated Circuit Systems – 32 kHz Motherboard Frequency Generator

Integrated
Circuit
Systems, Inc.
ICS9133X
32 kHz Motherboard Frequency Generator
General Description
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.
Features
• Single 32.768 kHz crystal generates all PC
motherboard clocks
• Cost-reduced version of popular ICS9132
• Contains internal crystal load capacitors and
feedback bias
• 3 independent clock generators
• Generates CPU clocks from 12.5 to 100 MHz
• Up to 7 output clocks
• Separate VDD for 32 kHz clock
• Output enable tristates outputs
• Power-down options available
• Operates from 3.3V or 5.0V supply
• Operates up to 66 MHz at 3.3V
• Skew controlled 1X and 2X CPU clocks
• 20-pin PDIP or SOIC package
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.
Block Diagram
9133X Rev A 052897P
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.