W83194R-39 Datasheet, PDF (1/21 Pages) Winbond – 100MHZ 3-DIMM CLOCK

W83194R-39/-39A
1.0 GENERAL DESCRIPTION
100MHZ 3-DIMM CLOCK
The W83194R-39/-39A is a Clock Synthesizer which provides all clocks required for high-speed RISC
or CISC microprocessor such as Intel Pentium II. W83194R-39 provides eight different frequency of
CPU and PCI clocks and W83194R-39A provides sixteen CPU/PCI frequencies which are externally
selectable with smooth transitions. W83194R-39/-39A also provides 13 SDRAM clocks controlled by
the none-delay buffer_in pin.
The W83194R-39/-39A accepts a 14.318 MHz reference crystal as its input and runs on a 3.3V
supply. Spread spectrum built in at ¡Ó0.5% or ¡Ó0.25% 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. It is not recommend to use the dual function pin for the slots(ISA, PCI, CPU, DIMM). The
add on cards may have a pull up or pull down.
High drive six PCI and thirteen SDRAM CLOCK outputs typically provide greater than 1 V /ns slew
rate into 30 pF loads. Two 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
• Supports Pentium™ II CPU with I²C.
• 2 CPU clocks (one free-running CPU clock)
• 13 SDRAM clocks for 3 DIMs
• 6 PCI synchronous clocks
• One IOAPIC clock for multiprocessor support
• Optional single or mixed supply:
(Vddq1=Vddq2 = Vddq3 = Vddq4 = VddL1 =VddL2= 3.3V) or (Vddq1= Vddq2 = Vddq3=Vddq4 =
3.3V, VddL1 = VdqL2 = 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 50 MHz to 133 MHz CPU
• I²C 2-Wire serial interface and I²C read back
Publication Release Date: May 1998
-1-
Revision 0.20