ICS9148-93 Datasheet | Integrated Circuit Systems

Integrated Circuit Systems, Inc. Advance Information Frequency Generator & Integrated Buffers for PENTIUM/Pro TM General Description The ICS9148-93 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 8d B to 10d B. This simplifies EMI qualification without resorting to board design iterations or costly shielding. The ICS9148-93 employs a proprietary closed loop design, which tightly controls the percentage of spreading over process and temperature variations. Serial programming I 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 • 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 – CPU<250ps - SDRAM – SDRAM < 250ps - CPU – SDRAM < 250ps - CPU(early) – PCI : 1-4ns Supports Spread Spectrum modulation +0.25, ±0.6% Serial I2C 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. • • • • • • 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) 9148-93 Rev - 1/22/99 48-Pin SSOP - Internal Pull-up Resistor of 240K to 3.3V on indicated inputs Pentium is a trademark of Intel Corporation I2C is a trademark of Philips Corporation ADVANCE INFORMATION documents contain information on products in the formative or design phase development. Characteristic...