W196

PRELIMINARY W196 Spread Spectrum FTG for 440BX and VIA Apollo Pro-133 Features Maximized EMI suppression using Cypress’s Spread Spectrum Technology System frequency synthesizer for 440BX, 440ZX, and VIA Apollo Pro-133 I2C programmable to 155 MHz (32 selectable frequencies) Two skew-controlled copies of CPU output 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 clock 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 CPU Cycle to Cycle Jitter: .......................................... 250 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: ........................ 1.5 to 4.0 ns (CPU Leads) REF2X/SEL48#, SCLOCK, SDATA: ............... 250-kΩ pull-up FS1: ............................................................250-kΩ pull-down FS0: ...................................................No pull-up or pull-down Note: Internal pull-up or pull-down resistors should not be relied upon for setting I/O pins HIGH or LOW. Table 1. Pin Selectable Frequency FS1 1 1 0 0 FS0 1 0 1 0 CPU(0:1) 133.3 MHz 105 MHz 100 MHz 66.8 MHz PCI 33.3 MHz 35 MHz 33.3 MHz 33.3 MHz Key Spe...