GENERAL DESCRIPTION

The W83194BR-645 is a Clock Synthesizer for SiS645/650 chipset. W83194BR-645 provides all clocks required for high-speed Intel Pentium 4, and also provides 32 different frequencies of CPU clocks frequency setting. All clocks are externally selectable with smooth transitions. The W83194BR- 645 makes SDRAM in synchronous or asynchronous frequency with CPU clocks.

FEATURES

• Supports Intel Pentium 4 CPU with I2C.

• 2 pairs of differential CPU clocks

• 2 ZCLK for SiS 645/650 chipset

• 2 AGP clocks

• 1 SDRAM output clock for chipset

• 8 PCI synchronous clocks

• 1 24/48 MHz, 1 48 MHz

• 3 REF clocks

• Skew --- CPU to SDRAM < 1 nS, PCI to PCI < 500 pS, AGP to AGP < 175 pS

• Smooth frequency switch with selections from 66 to 200 MHz

• I2C 2-Wire serial interface and I2C read back

• Flexible spread spectrum to reduce EMI

• Programmable registers to enable/stop each output and select modes (Mode as Tri-state or Normal)

• Packaged in 48-pin SSOP