Frequency Generator & Integrated Buffers - Integrated Circuit Systems
Description
Integrated Circuit Systems, Inc.
ICS9148-13
Frequency Generator & Integrated Buffers for PENTIUMTM
General Description
The ICS9148-13 generates all clocks required for high speed RISC or CISC microprocessor systems such as Intel Pentium and PentiumPro.
An output enable is provided for testability.
Spread Spectrum is available to modulate the CPU and BUS PLL (leaving the REF, 24, 48 MHz operating normally).
The SS_EN# pin enables the spreading when low.
The SS_TYPE pin choses ±0.
5% (nominally) center spread or +0, -2% (nominally) downspread modulation.
High drive BUS outputs typically provide greater than 1 V/ns slew rate into 30 pF loads.
CPU outputs typically provide better than 1V/ns slew rate into 20 pF loads while maintaining 50 ± 5% duty cycle.
The REF clock outputs typically provide better than 0.
8/ns slew rates.
Features
•
Generates twelve processor, six bus, two 14.
31818MHz, 24MHz and one 48MHz clock for USB support.
Synchronous clocks skew matched to 250 ps window on CPUs and 500 ps window on BUSs CPU to BUS skew, 3.
0 to 5.
0ns (CPU Early) 3.
0V - 3.
7V supply range 48-pin SSOP package
Pin Configuration
Block Diagram
48-Pin SSOP
Output Enable
OE REF 24 48 CPU (MHz) (MHz) BUS VCO OSC
Functionality
FS2 0 0 0 0 1 1 1 1 FS1 0 0 1 1 0 0 1 1 FS0 0 1 0 1 0 1 0 1 CPU (1:12) in MHz 75 100 75 83.
3 50 60 66.
67 55 BUS (1:6) MHz 37.
5 33.
3 30.
0 41.
65 25 30 33.
33 27.
5 in
1
Runs
Runs
Runs
Runs
Runs
Runs
Runs
0
Tristate
Tristate
Tristate
Tristate
Tristate
Runs
Runs
30K pullup resistor to VDD on OE, FS(0:2), SS_EN#, SS_TYPE
Pentium is a trademark of Intel Corporation
9148-13 Rev A 020398
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.
ICS9148-13
Pin Descriptions
PIN NUMBER 1, 2 3, 10, 18, 24, 30, 35, 43, 44 4 5 6 7,...
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