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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
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