Clock for SiS Chipsets

The W83194BG-703 is a Clock Synthesizer for SIS 741 chipset with 964 South Bridge, which provides all clocks required for high-speed microprocessor and provides step-less frequency programming and 32 different frequencies of CPU, PCI, and AGP clocks setting, support two ZCLK clock and one pair current mode differential SRC clock outputs; all clocks are externally selectable with smooth transitions.

W83194BG-703 supports I²C serial bus interface to program the registers to enable or disable each clock outputs and provides -0.5% and +/-0.25% center type spread spectrum or programmable S.S.T. scale to reduce EMI. It also has watchdog timer to support auto-reset when systems hanging caused by improper frequency setting.

W83194BG-703 accepts a 14.318 MHz reference crystal as its input and runs on a 3.3V supply.

• 1 3.3V open drain Differential pair clock outputs for CPU
• 1 3.3V open drain singled-ended clock output for chipset host bus.
• 1 pair 3.3V current mode differential SRC clock.
• 2x 3.3V ZCLK clock outputs, 2x AGP clock outputs, and 8 PCI synchronous clocks
• 2x 2.5V IOAPIC clock outputs, and 3x 14.318MHz REF clock outputs.
• 1x 24_48Mhz clock output for super I/O, and 1x 12_48 MHz clock output for USB.
• ZCLK/AGP/PCI clock out supports synchronous and asynchronous mode
• Smooth frequency switch with selections from 100 to 218MHz
• Step-less frequency programming and programmable clock outputs Skew control
• I²C 2-Wire serial interface and support byte read/write and block read/write.
• -0.5% and +/- 0.25% center type spread spectrum or programmable S.S.T. scale to reduce EMI
• Programmable registers to enable/stop each output and select modes