器件名称: W48S111
功能描述: Spread Spectrum Desktop/Notebook System Frequency Generator
文件大小: 137.88KB 共11页
简 介:PRELIMINARY
W48S111-14
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 133 MHz 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 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
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: ........................ 1.5 to 4.0 ns (CPU Leads) REF2X/SEL48#, SCLOCK, SDATA: ............... 250-k 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 GND PCI_F PCI1 PCI2 PCI3……
