Spread Spectrum System Frequency Synthesizer
PRELIMINARY
W133
Spread Spectrum System Frequency Synthesizer
Features
• Maximized EMI suppression using Cypress’s spr...
Description
PRELIMINARY
W133
Spread Spectrum System Frequency Synthesizer
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 for clock stop and shut down Available in 56-pin SSOP CPU Output Jitter: ...................................................... 250 ps CPUdiv2 Output Jitter:.................................................250 ps 48 MHz, 3V66, PCI, IOAPIC Output Jitter: .................. 500 ps CPU0:3, CPUdiv2_ 0:1 Output Skew: ......................... 175 ps PCI_F, PCI1:7 Output Skew: .......................................500 ps 3V66_0:3, IOAPIC0:2 Output Skew; ...........................250 ps CPU to 3V66 Output Offset: ............. 0.0–1.5 ns (CPU leads) 3V66 to PCI Output Offset:.............. 1.5–4.0 ns (3V66 leads) CPU to IOAPIC Output Offset: ......... 1.5–4.0 ns (CPU leads) Logic inputs, except SEL133/100#, have 250-kΩ pull-up resistors. Table 1. Pin Selectable Frequency[1] SEL133/100# 1 0 CPU0:3 (MHz) 133 MHz 100 MHz PC...
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