Integrated
Circuit
Systems, Inc.
ICS9148-58
Frequency Generator & Integrated Buffers for PENTIUM/Pro
TM
General Description
The
ICS9148-58
is the single chip clock solution for Desktop/
Notebook designs using the VIA MVP3 style chipset. It
provides all necessary clock signals for such a system.
Spread spectrum may be enabled through I2C programming.
Spread spectrum typically reduces system EMI by 8dB to
10dB. This simplifies EMI qualification without resorting to
board design iterations or costly shielding. The
ICS9148-58
employs a proprietary closed loop design, which tightly
controls the percentage of spreading over process and
temperature variations.
Serial programming I
2
C interface allows changing functions,
stop clock programming and frequency selection. The SD_SEL
latched input allows the SDRAM frequency to follow the
CPUCLK frequency(SD_SEL=1) or the AGP clock
frequency(SD_SEL=0)
Features
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Generates the following system clocks:
- 4 CPU(2.5V/3.3V) upto 100MHz.
- 6 PCI(3.3V) @ 33.3MHz
- 2AGP(3.3V) @ 2 x PCI
- 12 SDRAMs(3.3V) @ either CPU or AGP
- 2 REF (3.3V) @ 14.318MHz
Skew characteristics:
- CPU 聳 CPU<250ps
- SDRAM 聳 SDRAM < 250ps
- CPU 聳 SDRAM < 250ps
- CPU(early) 聳 PCI : 1-4ns
Spread Spectrum 0 to -5% down spread.
Serial I
2
C interface for Power Management, Frequency
Select, Spread Spectrum.
Efficient Power management scheme through PCI and CPU
STOP CLOCKS.
Uses external 14.318MHz crystal
48 pin 300mil SSOP.
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Block Diagram
Pin Configuration
Power Groups
VDD1 = REF (0:1), X1, X2
VDD2 = PCICLK_F, PCICLK(0:5)
VDD3 = SDRAM (0:11), supply for PLL core,
24 MHz, 48MHz
VDD4 = AGP (0:1)
VDDL = CPUCLK (0:3)
9148-58 Rev C 12/07/98
48-Pin SSOP
* Internal Pull-up Resistor of
240K to 3.3V on indicated inputs
Pentium is a trademark of Intel Corporation
I
2
C is a trademark of Philips Corporation
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.