Preliminary W83193R-02/-04/-04A
83.3 MHZ 3-DIMM CLOCK
1.0 GENERAL DESCRIPTION
The W83193R-02/-04/-04A is a Main board Clock Synthesizer which provides all clocks required for
high-speed RISC or CISC microprocessor such as Intel PentiumPro, PentiumII, AMD or Cyrix. Eight
different frequency of CPU and PCI clocks are externally selectable with smooth transitions.
The W83193R-02/-04/-04A also provides I2C serial bus interface to program the registers to enable
or disable each clock outputs and choose the 0.5% or 1.5% center type spread spectrum.
The W83193R-02/-04/-04A 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 1V /nS slew rate
into 30 pF loads. CPU CLOCK outputs typically provide better than 1V /nS slew rate into 20 pF loads
as maintaining 50
±5%
duty cycle. The fixed frequency outputs as REF, 24 MHz, and 48 MHz provide
better than 0.5V /nS slew rate.
2.0 FEATURES
•
Supports Pentium™, Pentium™ Pro, Pentium™ II, AMD and Cyrix CPUs with I C.
•
4 CPU clocks
•
12 SDRAM clocks for 3 DIMs.
•
7 PCI synchronous clocks.
•
One IOAPIC clock for multiprocessor support.
•
Optional single or mixed supply:
2
(V
DD
= V
DD
q3 = V
DD
q2 = V
DD
q2b = 3.3V) or (V
DD
= V
DD
q3 = 3.3V, V
DD
q2 = V
DD
2b = 2.5V)
•
< 250 pS skew among CPU and SDRAM clocks.
•
< 250 pS skew among PCI clocks.
•
Smooth frequency switch with selections from 50 MHz to 83.3 MHz CPU. (W83193R-04)
•
Smooth frequency switch with selections from 50 MHz to 112 MHz CPU. (W83193R-04A)
•
I C 2-Wire serial interface and I C read back.
•
Spread spectrum function to reduce EMI.
•
Programmable registers to enable/stop each output and select modes
2
2
(mode as Tri-state or Normal)
•
MODE pin for power Management
•
48 MHz for USB
•
24 MHz for super I/O
•
Packaged in 48-pin SSOP
-1-
Publication Release Date: April 1999
Revision A1
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