器件名称: W42C32
功能描述: Spread Spectrum Frequency Timing Generator
文件大小: 131.81KB 共8页
简 介:W42C32-05
Spread Spectrum Frequency Timing Generator
Features
Maximized EMI suppression using Cypress’s Spread Spectrum technology Generates a spread spectrum timing signal Reduces measured EMI by as much as 12 dB Integrated loop filter components Requires a single low-cost fundamental crystal (or other frequency reference) for proper operation Special spread spectrum control functions Low-power CMOS design Available in 16-pin SOIC package, (300 mil)
Key Specifications
Cycle-to-Cycle Jitter .................................................... 250 ps 45/55 Duty Cycle .................................... approximately 1.4V Selectable Frequency spread 2 ns rise/fall time 0.4V to 2.0V, 3.3V supply 2 ns rise/fall time 0.8V to 2.4V, 5.0V supply Table 1. Frequency Spread Selection W42C32-05 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 14.318 REFOUT (MHz) 22.1148 22.1148 14.7456 18.432 14.318 CLKOUT (MHz) 44.2296 ± 2.5% 44.2296 ±1.5% 29.4912 ± 2.5% 18.432 ± 2.5% 66.66 – 2% Reserved 100 – 2% Reserved VDD (V) 5.0 5.0 5.0 5.0 3.3 3.3 3.3 3.3
Overview
The W42C32 modulates the output of a single PLL in order to ‘spread’ the bandwidth of a synthesized clock and, more importantly, decrease the peak amplitudes of its fundamental harmonics. Since peak amplitudes are reduced, the radiated electromagnetic emissions of the W42C32-05 are significantly lower than the typical narrow band signal produced by oscillators and most frequency generators. Lowering a signal’s ampl……
