器件名称: W48S87
功能描述: Spread Spectrum 3 DIMM Desktop Clock
文件大小: 201.41KB 共21页
简 介:PRELIMINARY
W48S87-04
Spread Spectrum 3 DIMM Desktop Clock
Features
Outputs — 4 CPU Clock (2.5V or 3.3V, 50 to 83.3 MHz) — 7 PCI (3.3V) — 1 48-MHz for USB (3.3V) — 1 24-MHz for Super I/O (3.3V) — 2 REF (3.3V) — 1 IOAPIC (2.5V or 3.3V) — 12 SDRAM Serial data interface provides additional frequency selection, individual clock output disable, and other functions Smooth transition supports dynamic frequency assignment Frequency selection not affected during power down/up cycle Supports a variety of power-saving options 3.3V operation Available in 48-pin SSOP (300 mils)
Key Specifications
±0.5% Spread Spectrum Modulation: ......................... ±0.5% Jitter (Cycle-to-Cycle): .................................................250 ps Duty Cycle: ................................................................ 45-55% CPU-PCI Skew: ........................................................ 1 to 4 ns PCI-PCI or CPU-CPU Skew: .......................................250 ps Table 1. Pin Selectable Frequency[1] Input Address FS2 0 0 0 0 1 1 1 1 FS1 0 0 1 1 0 0 1 1 FS0 0 1 0 1 0 1 0 1 CPU, SDRAM Clocks (MHz) 50.0 75.0 83.3 68.5 55.0 75.0 60.0 66.8 PCI Clocks (MHz) 25.0 32.0 41.65 34.25 27.5 37.5 30.0 33.4
Block Diagram
SDATA SCLOCK Serial Port Device Control PLL Ref Freq X1 X2 CPU3.3#_2.5 FS0 FS1 FS2 XTAL OSC CPU Clock Mode Control Freq Select I/O MODE VDDL1 IOAPIC PLL1 VDDL2 Stop Clock Cntrl CPU_STOP# ÷2 4 CPU0:3 VDD3 12 SDRAM0:11 VDD2 I/O I/O 4 PCI_F/FS1 PCI0/FS2 PCI1:4 PCI5(PWR_……
