W83194AR-W
150MHZ CLOCK FOR WHITNEY CHIPSET
1.0 GENERAL DESCRIPTION
The W83194AR-W is a Clock Synthesizer for Intel Whitney chipset. W83194AR-W 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 W83194AR-W provides I
2
C serial bus interface to program the registers to enable or disable
each clock outputs and provides 0.5% and 0.75% center type spread spectrum to reduce EMI.
The W83194AR-W 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¡Ó 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
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2 CPU clocks
9 SDRAM clocks for 2 DIMMs
8 PCI synchronous clocks.
Optional single or mixed supply:
(VddR = VddP=VddS = Vdd48 = Vdd3 = 3.3V, VddA=VddC=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 150MHz
I
2
C 2-Wire serial interface and I
2
C read back
0.5% and 0.75% 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
48-pin SSOP package
-1-
Publication Release Date: May. 1999
Revision 0.50
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