ICS9248-95 Datasheet, PDF (1/16 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for PENTIUM/ProTM

Integrated
Circuit
Systems, Inc.
ICS9248 - 95
Frequency Generator & Integrated Buffers for PENTIUM/Pro^TM
General Description
The ICS9248-95 is the single chip clock solution for Desktop
designs using the VIA MVP4 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 ICS9248-95
employs a proprietary closed loop design, which tightly
controls the percentage of spreading over process and
temperature variations.
Block Diagram
Features
• Up to 124MHz frequency support.
• Spread Spectrum for EMI control ±0.5% center
spread and ±0.25% center spread
• Serial I²C interface for Power Management,
Frequency Select, Spread Spectrum.
• Provides the following system clocks
- 4-CPUs @ 3.3V, up to 124MHz.
- 13-SDRAMs @3.3V, up to 124MHz
(including SDRAM_F)
- 6-PCI @3.3V, CPU/2 or CPU/3
(including PCICLK_F)
(including 1 free running).
- 1-24MHz @3.3V fixed.
- 1-48MHz @3.3V fixed.
- 2-REF @3.3V, 14.318MHz.
• Efficient Power management scheme through PCI
and STOP CLOCKS.
• Spread Spectrum ±.25%, & ±.5% center spread
Pin Configuration
Power Groups
VDDCPU, GNDCPU = CPUCLK [2:0], CPUCLK_F
VDDSDR, GNDSDR = SDRAMCLKS [11:0], SDRAM_F
VDDPCI, GNDPCI = PCICLKS [4:0], PCICLK_F
VDD48 = 48MHz, 24MHz
VDDREF, GNDREF = REF, X1, X2
310D—04/12/05
48-Pin SSOP
* Internal Pull-up Resistor of 240K to VDD
Pentium is a trademark of Intel Corporation
I²C is a trademark of Philips Corporation