W83194BR-250

The W83194BR-250 is a Clock Synthesizer for VIA Pro266 chipset. W83194BR-250 provides all clocks required for high-speed RISC or CISC microprocessor and also provides 64 different frequencies of CPU, PCI, AGP, IOAPIC clocks frequency setting. All clocks are externally selectable with smooth transitions.

The W83194BR-250 provides I2C serial bus interface to program the registers to enable or disable each clock outputs and provides 0.25% and 0.5% center type spread spectrum to reduce EMI.

The W83194BR-250 provides stepless frequency programming by controlling the VCO freq. and the clock output divisor ratio. Also the skew of CPU and AGP clock outputs are programmable. A watch dog timer is quipped and when time out, the RESET# pin will output 4ms pulse signal.

The W83194BR-250 accepts a 14.318 MHz reference crystal as its input and runs on a 3.3V supply. High drive PCI CLOCK outputs typically provide greater than 1 V /ns slew rate into 30 pF loads. CPU CLOCK outputs typically provide better than 1 V /ns slew rate into 20 pF loads as maintaining 50± 5% duty cycle. The fixed frequency outputs as REF, 24MHz, and 48 MHz provide better than 0.5V /ns slew rate.