3

ICS950401

0499C—11/01/04

General Description

The ICS950401 is a main clock synthesizer chip for AMD-K8. This provides all clocks required for Clawhammer and

Sledgehammer systems.

Spread spectrum may be enabled through I

2C 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 ICS950401

employs a proprietary closed loop design, which tightly controls the percentage of spreading over process and

temperature variations.

Serial programming I

2C interface allows changing functions, stop clock programming and frequency selection.

Power Groups

VDDA = PLL2

Pin 32

VDDA = VDD for Core PLL

Pin 43

VDDREF = REF, Xtal

Pin 2

Skew Characteristics

Parameter

Description

Test Conditons

Skew

Window

Unit

Tsk_CPU_CPU

measured at x-ing of CPU,

250

ps

Tsk_CPU_PCI

measured at x-ing of CPU,

1.5V of PCI clock

2000

ps

Tsk_PCI_PCI

measured between rising

edge at 1.5V

500

ps

Tsk_PCI33-HT66

measured between rising

edge at 1.5V

500

ps

Tsk_CPU_HT66

measured between rising

edge at 1.5V

2000

ps

Tsk_CPU_HT66

measured at x-ing of CPU,

1.5V of PCI clock

500

ps

Tsk_CPU_CPU

measured at x-ing of CPU,

200

ps

Tsk_CPU_PCI

measured at x-ing of CPU,

1.5V of PCI clock

200

ps

Tsk_PCI_PCI

measured between rising

edge at 1.5V

200

ps

Tsk_PCI33-HT66

measured between rising

edge at 1.5V

200

ps

Tsk_CPU_HT66

measured between rising

edge at 1.5V

200

ps

Tsk_CPU_HT66

measured at x-ing of CPU,

1.5V of PCI clock

200

ps

time independent

skew

not dependent on

V, T changes

time variant skew

varies over

V, T changes