
Cypress Semiconductor
Overview
The W199 was developed as a single-chip device to meet the clocking needs of the VIA Apollo Pro-133 core logic chip set. In addition to the typical outputs provided by standard 100-MHz FTGs, the W199 adds a thirteenth output buffer, supporting SDRAM DIMM modules in conjunction with the chipset.
Cypress’s proprietary spread spectrum frequency synthesis technique is a feature of the CPU and PCI outputs. When enabled, this feature reduces the peak EMI measurements of not only the output signals and their harmonics, but also of any other clock signals that are properly synchronized to them.
FEATUREs
• Maximized EMI suppression using Cypress’s Spread Spectrum Technology
• Single-chip system frequency synthesizer for VIA Apollo Pro-133
• 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
• 13 SDRAM outputs provide support for 3 DIMMs
• Supports frequencies up to 150 MHz
• I2C™ interface for programming
• Power management control inputs
• Available in 48-pin SSOP