Integrated
Circuit
Systems, Inc.
General Description
Features
ICS9148-58
Block Diagram
Pentium is a trademark of Intel Corporation
I
2C is a trademark of Philips Corporation
Frequency Generator & Integrated Buffers for PENTIUM/ProTM
9148-58 Rev C 12/07/98
Pin Configuration
Generates the following system clocks:
-4CPU(2.5V/3.3V)upto100MHz.
-6PCI(3.3V)@ 33.3MHz
-2AGP(3.3V)@2x PCI
- 12 SDRAMs(3.3V) @ either CPU orAGP
-2REF(3.3V)@14.318MHz
Skew characteristics:
- CPU CPU<250ps
- SDRAM SDRAM < 250ps
- CPU SDRAM < 250ps
- CPU(early) PCI : 1-4ns
Spread Spectrum 0 to -5% down spread.
Serial I2C interface for Power Management, Frequency
Select, Spread Spectrum.
Efficient Power management scheme through PCI and CPU
STOPCLOCKS.
Uses external 14.318MHz crystal
48pin300milSSOP.
48-Pin SSOP
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)
* Internal Pull-up Resistor of
240K to 3.3V on indicated inputs
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 I2C 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)
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.