Integrated
Circuit
Systems, Inc.
ICS9147-22
Pentium/Pro
TM
System and Cyrix Clock Chip
General Description
The
ICS9147-22
is a Clock Synthesizer chip for Pentium
and PentiumPro plus Cyrix CPU based Desktop/Notebook
systems that will provide all necessary clock timing.
Features include four CPU, seven PCI and eight SDRAM
clocks. Two reference outputs are available equal to the
crystal frequency, plus the IOAPIC output powered by
VDDL. Additionally, the device meets the Pentium power-
up stabilization, which requires that CPU and PCI clocks
be stable within 2ms after power-up.
High drive PCICLK and SDRAM outputs typically provide
greater than 1 V/ns slew rate into 30 pF loads. CPUCLK
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 0.5V/ns slew
rates.
The
ICS9147-22
accepts a 14.318MHz reference crystal
or clock as its input and runs on a 3.3V supply.
Features
Generates system clocks for CPU, IOAPIC, SDRAM,
PCI, plus 14.318 MHz (REF0:1), USB, Super I/O
Supports single or dual processor systems
Supports Intel 60, 66.8MHz, Cyrix 55, 75MHz plus 83.3
and 68MHz (Turbo of 66.6) speeds.
Synchronous clocks skew matched to 250ps window on
CPU, SDRAM and 500ps window on PCI clocks
CPU clocks to PCI clocks skew 1-4ns (CPU early)
Two fixed outputs, 48MHz and 24 MHz
Separate 2.5V and 3.3V supply pins
- 2.5V or 3.3V output: CPU, IOAPIC
- 3.3V outputs: SDRAM, PCI, REF, 48/24 MHz
No power supply sequence requirements
48 pin 300 mil SSOP
Pin Configuration
Block Diagram
48-Pin SSOP
Power Groups
VDD1 = REF (0:1), X1, X2
VDD2 = PCICLK_F, PCICLK (0:5)
VDD3 = SDRAM (0:7),
VDD4 = 48MHz, 24MHz
VDDL = IOAPIC, CPUCLK (0:3)
Pentium is a trademark on Intel Corporation.
9147-22 Rev A 072597P
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.
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