W158 Datasheet

W158 Spread Spectrum System Frequency Synthesizer

41, 42, 45, 46 O CPU Clock Outputs 0 through 3: These four CPU clocks run at a frequency set by SEL133/100#. Output voltage swing is set by the voltage applied to VDDQ2. CPUdiv2_ 0:1 49, 50 O Synchronous Memory Reference Clock Output 0 through 1: Reference clock for Direct RDRAM clock generators run.

Features

• Maximized EMI suppression using Cypress’s spread spectrum technology
• Intel® CK98 Specification compliant
• 0.5% downspread outputs deliver up to 10 dB lower EMI
• Four skew-controlled copies of CPU output
• Eight copies of PCI output (synchronous w/CPU output)
• Four copies of 66-MHz fixed frequency 3.3V clock
• Two copies of CPU/2 outputs for synchronous memory reference
• Three copies of 16.67-MHz IOAPIC clock, synchronous to CPU clock
• One copy of 48-MHz USB output
• Two copies of 14.31818-MHz reference clock
• Programmable to 133- or 100-MHz operation
• Power management control pins f.