GENERAL DESCRIPTION

The W83194R-81 is a Clock Synthesizer for SiS chipset. W83194R-81 provides all clocks required for high-speed RISC or CISC microprocessor such as AMD,Cyrix,Intel Pentium and also provides 16 different frequencies of CPU clocks frequency setting. All clocks are externally selectable with smooth transitions. The W83194R-81 makes SDRAM in synchronous or asynchronous frequency with CPU clocks.

PRODUCT FEATURES

• Supports PentiumÔ, PentiumÔ Pro, AMD and Cyrix CPUs with I2C.

• 3 CPU clocks

• 13 SDRAM clocks for 3 DIMMs

• 6 PCI synchronous clocks.

• Optional single or mixed supply:

(Vdd = Vddq4=Vddq3 = Vddq2b = 3.3V, Vddq2=2.5V) or

(Vdd = Vddq4=Vddq3 = 3.3V, Vddq2=Vdq2b = 2.5V)

• Skew form CPU to PCI clock -1 to 4 ns, center 2.6 ns

• SDRAM frequency synchronous or asynchronous to CPU clocks

• Smooth frequency switch with selections from 66 to 133mhz(including 90MHz)

• I2C 2-Wire serial interface and I2C read back

• 0.25, 0.5 center type spread spectrum to reduce EMI

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

(mode as Tri-state or Normal )

• MODE pin for power Management

• 48 MHz for USB

• 24 MHz for super I/O

• 48-pin SSOP package