W83195BR-S
STEPLESS 200MHZ 3-DIMM CLOCK FOR SOLANO CHIPSET
1.0 GENERAL DESCRIPTION
The W83195BR-S is a Clock Synthesizer for Intel 815 Solano chipset. W83195BR-S provides all
clocks required for high-speed RISC or CISC microprocessor and also provides 64 different
frequencies of CPU, SDRAM, PCI, 3V66, IOAPIC clocks frequency setting. All clocks are externally
selectable with smooth transitions.
The W83195BR-S 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. A watch
dog timer is quipped and when time out, the RESET# pin will output 4ms pulse signal.
The W83195BR-S provides stepless frequency programming by controlling the VCO freq. and the
clock output divisor ratio. Also the skew of CPU, SDRAM and 3V66 clock outputs are programmable.
The W83195BR-S accepts a 14.318 MHz reference crystal as its input and runs on a 3.3V supply.
High drive PCI and SDRAM 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.
2.0 PRODUCT FEATURES
• 2 CPU clocks
• 3 3V66 for chipset and AGP clocks
• 12 SDRAM clocks for 3 DIMMs
• 8 PCI synchronous clocks.
• Optional single or mixed supply:
(VddR = VddP=VddS = Vdd48 = Vdd3 = 3.3V, VddLAPIC=VddLCPU=2.5V)
• Skew form CPU to PCI clock -1 to 4 ns, center 2.6 ns
• Smooth frequency switch with selections from 66.8 to 200 MHz
• I2C 2-Wire serial interface and I2C read back
• 0.25% and 0.5% center type spread spectrum
• Programmable registers to enable/stop each output and select modes
(mode as Tri-state or Normal )
• Two 48 MHz pins for USB
• 24 MHz for super I/O
• 56-pin SSOP package
Publication Release Date: June 2000
-1-
Revision 0.42