ICS9248-101 Datasheet | Integrated Circuit Systems

Integrated Circuit Systems, Inc. Frequency Generator & Integrated Buffers for PENTIUM/Pro TM & K6 General Description The ICS9248-101 is the single chip clock solution for Notebook designs using the 440BX or the VIA Apollo Pro 133 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 8d B to 10d B. This simplifies EMI qualification without resorting to board design iterations or costly shielding. The ICS9248-101 employs a proprietary closed loop design, which tightly controls the percentage of spreading over process and temperature variations. • • Features • • • • Up to 137MHz frequency support Spread Spectrum for EMI control Serial I2C interface for Power Management, Frequency Select, Spread Spectrum. Provides the following system clocks - 4-CPUs @ 2.5/3.3V, up to 137MHz. (including CPUCLK_F) - 9-SDRAMs @3.3V, up to 137MHz (including SDRAM_F) - 8-PCI @3.3V, CPU/2 or CPU/3 (including 1 free running PCICLK_F) - 1-24/48MHz @3.3V - 1-48MHz @3.3V fixed - 2-REF @3.3V, 14.318MHz. Efficient Power management scheme through PCI and STOP CLOCKS Spread Spectrum ± .25%, & 0 to -0.5% down spread Block Diagram Pin Configuration VDDREF REF0 GNDREF X1 X2 VDDPCI - CPU2.5_3.3#/PCICLK_F - FS3/PCICLK0 GNDPCI - SEL24_48#/PCICLK1 PCICLK2 PCICLK3 PCICLK4 VDDPCI BUFFER IN GNDPCI PCICLK5 PCICLK6 VDDCOR PCI_STOP# - PD# GND48 SDATA 2 I C SCLK 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 REF1/FS2- VDDLCPU CPUCLK_F CPUCLK0 GNDLCPU CPUCLK1 CPUCLK2 CLK_STOP# GNDSDR SDRAM_F SDRAM0 SDRAM1 VDDSDR SDRAM2 SDRAM3 GNDSDR SDRAM4 SDRAM5 VDDSDR SDRAM6 SDRAM7 VDD48 48MHz/FS0- 24_48MHz/FS1- { Power Groups VDDLCPU, GNDLCPU = CPUCLK [2:0], CPUCLK_F VDDSDR, GNDSDR = SDRAMCLKS [7:0], SDRAM_F VDDPCI, GNDPCI = PCICLKS [6:0], PCICLK_F VDD48, GND48 = 48MHz, 24MHz VDDREF, GNDREF = REF, X1, X2...