器件名称: W48S101
功能描述: Spread Spectrum Motherboard Frequency Generator
文件大小: 143.86KB 共12页
简 介:PRELIMINARY
W48S101-04
Spread Spectrum Motherboard Frequency Generator
Features
Maximized EMI suppression using Cypress’s Spread Spectrum technology I2C interface Four copies of CPU output Eight copies of PCI clock (synchronous w/CPU output) Two copies of 14.318-MHz IOAPIC output One copy of 48-MHz USB output Selectable 24-/48-MHz clock-through-resistor strapping Three buffered copies of 14.318-MHz reference input Input is a 14.318-MHz XTAL or reference signal Selectable 100-MHz or 66-MHz CPU outputs Power management control input pins Test mode and output three-state through I2C interface
Key Specifications
Supply Voltages:....................................... VDDQ3 = 3.3V±5% VDDQ2 = 2.5V±5% CPU Cycle to Cycle Jitter: ........................................... 200 ps CPU0:3 Output Skew: ................................................ 175 ps PCI_F, PCI1:7 Output Skew: .......................................500 ps CPU to PCI Output Skew: ............ 1.5 to 4.0 ns (CPU Leads) Logic inputs and REF0/SEL48# have 250K pull-up resistors except SEL100/66#. Table 1. Pin Selectable Frequency SEL 100/66# 0 1 CPU (MHz) 66.8 100
[1]
PCI (MHz) 33.4 33.3
SPREAD#=0 ±0.5% Center ±0.5% Center
Block Diagram
VDDREF REF0/SEL48# X1 X2 XTAL OSC PLL Ref Freq VDDCORE0/1 GNDCORE0/1 REF1 REF2 GNDREF VDDAPIC APIC0 APIC1 GNDAPIC VDDCPU0 CPU0 Stop Clock Control 100/66#_SEL PLL 1 ÷2/÷3 SPREAD# CPU1 GNDCPU0 VDDCPU1 CPU2 CPU3 GNDCPU1 VDDPCI0 PCI_F Stop Clock Control PCI_STOP# PCI1 PCI2……
