ICS9133X
Integrated
Circuit
Systems, Inc.
32 kHz Motherboard Frequency Generator
Features
General Description
TheICS9133Xis 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.
Thedevicegeneratesthe14.318MHzsystemclock, eliminating
theneedfora14.318MHzcrystal.Highperformanceapplications
may require high speed clock termination components. The
chip includes three independent clock generators plus the
32.768kHzreferenceclocktoproduceallnecessaryfrequencies,
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
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Cost-reduced version of popular ICS9132
Contains internal crystal load capacitors and
feedback bias
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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
Applications
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.
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.
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
oforder.IntegratedCircuitSystemsalsooffersstandard versions,
such as that described in this data sheet.
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.