W164

W164 Spread Spectrum Desktop/Notebook System Frequency Generator Features Maximized EMI suppression using Cypress’s Spread Spectrum technology Reduces measured EMI by as much as 10 dB I2C programmable to 153 MHz (16 selectable frequencies) Two skew-controlled copies of CPU output SEL100/66# selects CPU frequency (100 or 66.8 MHz) Seven copies of PCI output (synchronous w/CPU output) One copy of 14.31818-MHz IOAPIC output One copy of 48-MHz USB output Selectable 24-/48-MHz output is determined by resistor straps on power-up One high-drive output buffer that produces a copy of the 14.318-MHz reference Isolated core VDD pin for noise reduction Key Specifications Supply Voltages:....................................... VDDQ3 = 3.3V±5% VDDQ2 = 2.5V±5% CPU Cycle to Cycle Jitter: ........................................... 200 ps CPU, PCI Output Edge Rate: ......................................... ≥1 V/ns CPU0:1 Output Skew: ................................................ 175 ps PCI_F, PCI1:6 Output Skew: .......................................500 ps CPU to PCI Skew: .............................. 1 to 4 ns (CPU Leads) REF2X/SEL48#, SCLOCK, SDATA ................ 250-kΩ pull-up Note: Internal pull-up resistors should not be relied upon for setting I/O pins HIGH. Table 1. Pin Selectable Frequency SEL100/66# 1 0 CPU(0:1) 100 MHz 66.8 MHz PCI 33.3 MHz 33.4 MHz Block Diagram VDDQ3 REF2X/SEL48# GND X1 X2 XTAL OSC PLL Ref Freq VDDQ3 IOAPIC Pin Configuration X1 X2...