GENERAL DESCRIPTION

The W83194BR-640 is a Clock Synthesizer for SiS 640 chipset. W83194BR-640 provides all clocks required for high-speed RISC or CISC microprocessor such as Intel Pentium II, Pentium III and Celeron, and also provides 16 different frequencies of CPU clocks frequency setting. All clocks are externally selectable with smooth transitions. The W83194BR-640 makes SDRAM in synchronous or asynchronous frequency with CPU clocks.

PRODUCT FEATURES

• Supports Intel Slot 1 and Socket 370 CPUs with I2C.

• 2 CPU clocks

• 2 AGP clocks

• 1 SDRAM output clock for chipset

• 1 IOAPIC clock

• 6 PCI synchronous clocks.

• Optional single or mixed supply:

(Others Vdd = 3.3V, VddLCPU=2.5V)

• Skew --- CPU to CPU < 175ps, CPU to SDRAM < 250ps, PCI to PCI < 500ps, AGP to AGP < 175ps

• Smooth frequency switch with selections from 66 to 200mhz

• I2C 2-Wire serial interface and I2C read back

• 0.5, 0.25center type, 0~0.5 down type spread spectrum to reduce EMI

• Programmable registers to enable/stop each output and select modes

(mode as Tri-state or Normal )

• 48 MHz for USB

• 24 MHz for super I/O

• Packaged in 48-pin SSOP