General Description

The ICS9248-141 is a main clock synthesizer chip for AMD-K7 based systems with VIA style chipset. This provides all clocks required 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 ICS9248-141 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.

Features:

• Up to 166MHz frequency support

• Support power management: CPU stop and Power down Mode from I2C programming.

• Spread spectrum for EMI control (± 0.25 center spread).

• Uses external 14.318MHz crystal

Output Features:

• 1 - Differential pair open drain CPU clocks

• 1 - Single-ended open drain CPU clock

• 13 - SDRAM @ 3.3V

• 6 - PCI @3.3V,

• 1 - 48MHz, @3.3V fixed.

• 1 - 24/48MHz @ 3.3V

• 2 - REF @3.3V, 14.318MHz.

Recommended Application:

VIA KX133 style chipset