GENERAL DESCRIPTION The W83194BR-39B is a Clock Synthesizer which provides all clocks required for high-speed RISC or CISC microprocessor such as Intel Pentium II or Pentium III. W83194BR-39B provides 64 CPU/PCI frequencies which are selectable with smooth transitions by hardware or software. W83194BR-39B also provides 13 SDRAM clocks controlled by the none-delay buffer_in pin. PRODUCT FEATURES • Supports PentiumÔ II and !!! CPU with I2C. • 2 CPU clocks (one free-running CPU clock) • 13 SDRAM clocks for 3 DIMMs • 6 PCI synchronous clocks • One IOAPIC clock for multiprocessor support • Optional single or mixed supply: (Vddq1=Vddq2 = Vddq3 = Vddq4 = VddL1 =VddL2= 3.3V) or (Vddq1= Vddq2 = Vddq3=Vddq4 = 3.3V, VddL1 = VddL2 = 2.5V) • < 250ps skew among CPU and SDRAM clocks • < 250ps skew among PCI clocks • < 5ns propagation delay SDRAM from buffer input • Skew from CPU (earlier) to PCI clock 1 to 4ns, center 2.6ns. • Smooth frequency switch with selections from 66 MHz to 200 MHz CPU • Step-less frequency programming by controlling the VCO freq. and the clock output divisor ratio • I2C 2-Wire serial interface and I2C read back • ±0.25% or ±0.5% spread spectrum function to reduce EMI in freq. table mode • Programmable spread spectrum in the M/N step-less mode • Programmable registers to enable/stop each output and select modes • MODE pin for power Management • RESET# out when watch dog timer time out • One 48 MHz for USB & one 24 MHz for super I/O • 48-pin SSOP package
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