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CYIFS731: Low EMI Spread Spectrum Clock | Cypress Semiconductor

CYIFS731: Low EMI Spread Spectrum Clock

Last Updated: 
Aug 25, 2015

Low EMI Spread Spectrum Clock


  • Reduces Systemic EMI.
  • Modulates external clocks including crystals, crystal oscillators and ceramic resonators.
  • 1X and 2X modulated frequency outputs.
  • Modulation programmable with simple external loop filter (LF).
  • 4 to 68 MHz operating frequency range.
  • Digitally controlled modulation.
  • TTL/CMOS compatible outputs.
  • Center Spread Modulation.
  • Low short term jitter.
  • For more, see pdf.

Functional Description

The CYIFS731 is a Frequency Spreading EMI Attenuator designed for the purpose of reducing Electro Magnetic Interference (EMI) found in today’s high speed digital systems. The CYIFS731 uses a proprietary technique to modulate the output clock, Modout. By modulating the frequency of the digital clock, measured EMI at the fundamental and harmonic frequencies is greatly reduced. This reduction in radiated energy can significantly reduce the cost of complying with regulatory requirements without degrading digital waveforms.