General Description

The ICS9248-168 is a main clock synthesizer chip for AMD-K7 based note book 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 ICS9248-168 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.

Output Features:

• 1 - Differential pair open drain CPU clocks

• 1 - CPU clock @ 3.3V

• 7 - SDRAM @ 3.3V

• 8 - PCI @ 3.3V,

• 1 - 48MHz, @ 3.3V fixed.

• 1 - 24/48MHz @ 3.3V

• 3 - REF @ 3.3V, 14.318MHz.

Features:

• Up to 153MHz frequency support

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

• Spread spectrum for EMI control (± 0.25 to ± 0.6 center, or 0 to -0.5 or -1.0 down spread).

• Uses external 14.318MHz crystal

Recommended Application:

VIA KT133 style chipset