General Description

The ICS9250-28 is part of a two chip clock solution for 810/810E and 815 type chipset. Combined with the ICS9112-17, the ICS9250-28 provides all necessary clock signals for such a system.

Spread spectrum may be enabled through I2C programming. Spread spectrum typically reduces EMI by 8dB to 10 dB. This simplifies EMI qualification without resorting to board design iterations or costly shielding. The ICS9250-28 employs a proprietary closed loop design, which tightly controls the percentage of spreading over process and temperature variations.

Features:

• Supports spread spectrum modulation, 0 to -0.5 down spread.

• I2C support for power management

• Efficient power management scheme through PD#

• Uses external 14.138 MHz crystal

• Alternate frequency selections available through I2C control.

Output Features:

• 2 CPU (2.5V) (up to 133MHz achievable through I2C)

• 13 SDRAM (3.3V) (up to 133MHz achievable through I2C)

• 2 PCI (3.3 V) @33.3MHz

• 1 IOAPIC (2.5V) @ 33.3 MHz

• 3 Hublink clocks (3.3 V) @ 66.6 MHz

• 2 (3.3V) @ 48 MHz (Non spread spectrum)

• 1 REF (3.3V) @ 14.318 MHz

Recommended Application:

810/810E and 815 type chipset.