Overview
The W48S87-04, a motherboard clock synthesizer, can provide either a 2.5V or 3.3V CPU clock swing, making it suitable for a variety of CPU options. Twelve SDRAM clocks are provided in phase with the CPU clock outputs. This provides clock support for up to three SDRAM DlMMs. Fixed output frequency clocks are provided for other system functions.

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)