W149 - Cypress Semiconductor

W149 440BX AGPset Spread Spectrum Frequency Synthesizer

CPU Clock Outputs: See Tables 2 and 6 for detailed frequency information. Output voltage swing is controlled by voltage applied to VDDQ2. PCI Clock Outputs 1 through 5: These five PCI clock outputs are controlled by the PCI_STOP# control pin. Output voltage swing is controlled by voltage applied to VDDQ3. Fixed PCI Clock Output: Frequency is set by the FS0:1.

Features

• Maximized EMI suppression using Cypress’s Spread Spectrum Technology
• Single chip system frequency synthesizer for Intel® 440BX AGPset
• Two copies of CPU output
• Six copies of PCI output
• One 48-MHz output for USB
• One 24-MHz output for SIO
• Two buffered reference outputs
• One IOAPIC output
• Thirteen SDRAM outputs provide support for 3 DIMMs
• Spread Spectrum feature always enabled
• I2C™ interface for programming
• Power management control inputs
• Smooth CPU frequency switching from 66.8
  –124 MHz VDDQ3: ...... 3.3V±5% VD.