Document
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)
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 amplitude by increasing its bandwidth is a method of reducing EMI called ‘spre.