器件名称: W42C31
功能描述: Spread Spectrum Frequency Timing Generator
文件大小: 119.62KB 共7页
简 介:W42C31-09
Spread Spectrum Frequency Timing Generator
Features
Maximized EMI suppression using Cypress’s Spread Spectrum technology Generates a spread spectrum copy of the provided input Integrated loop filter components Operates with a 3.3V or 5V supply Low-power CMOS design Available in 8-pin SOIC (Small Outline Integrated Circuit) to pass increasingly difficult EMI testing without resorting to costly shielding or redesign. In a system, not only is EMI reduced in the various clock lines, but also in all signals which are synchronized to the clock. Therefore, the benefits of using this technology increase with the number of address and data lines in the system. The Simplified Block Diagram shows a simple implementation. Table 1. Frequency Spread Selection W42C31-09 FS1 0 0 1 1 FS0 0 1 0 1 Input Frequency (MHz) 30 to 55 30 to 55 30 to 55 30 to 55 Output Frequency (MHz) fIN ±0.625% fIN ±1.25% fIN ±2.5% fIN –3.75%
Overview
The W42C31-09 incorporates the latest advances in PLL spread spectrum frequency synthesizer techniques. By frequency modulating the output with a low-frequency carrier, EMI is greatly reduced. Use of this technology allows systems
Simplified Block Diagram
Pin Configuration
VDD CLKIN NC GND FS1 1 2 3 4
SOIC W42C31-09 8 7 6 5 SSON# CLKOUT FS0 VDD
Oscillator or Reference Input
W42C31-09
Spread Spectrum Output (EMI suppressed)
Cypress Semiconductor Corporation
3901 North First Street
San Jose
CA 95134 408-943-2600 January 25, 2000, rev. *……
