W83194BR-39B Datasheet | Winbond

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. The W83194BR-39B provides step-less frequency programming by controlling the VCO freq. and the programmable PCI clock output divisor ratio. A watch dog timer is quipped and when time out, the RESET# pin will output 4ms pulse signal. The W83194BR-39B accepts a 14.318 MHz reference crystal as its input. Spread spectrum built in at ±0.5% or ±0.25% to reduce EMI. Programmable stopping individual clock outputs and frequency selection through I2C interface. The device meets the Pentium power-up stabilization, which requires CPU and PCI clocks be stable within 2 ms after power-up. Using dual function pin for the slots(ISA, PCI, CPU, DIMM) is not remend. 2.0 PRODUCT FEATURES - - - - - - Supports Pentium™ 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 = Vdd L1 =Vdd L2= 3.3V) or (Vddq1= Vddq2 = Vddq3=Vddq4 = 3.3V, Vdd L1 = Vdd L2 = 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...