Spread-spectrum clock generators combat EMI at source

Reducing radiated EMI usually involves adding expensive filtering or shielding, but Cypress Semiconductor’s Spread-Spectrum Clock Generators (SSCGs) minimise EMI at source by reducing the peak energy contained in clock harmonics.

Cypress currently has 35 SSCG products, providing designers with a wide range of options to optimise EMI performance in new-product designs. These save reliance on conventional EMI-containment components, thereby achieving system-level cost savings. Built-in features include On/Off control allowing use of spread-spectrum operation on a need-only basis, as well as a frequency-select feature that allows users to select from multiple frequencies on the same output pin.

By frequency-modulating the clock, Cypress’s SSCGs spread the total clock energy over a range of frequencies to prevent concentration of energy at a single frequency. As the frequency band is made wider, the energy peak is reduced, enabling significant peak energy reductions of 2dB to 20dB.

SSCG also allows modulation to be maintained as clock signals are propagated to their destinations.

 

FEATURES Peak EMI reduction on every harmonic Programmable peak-energy reduction and profile for optimising EMI reduction Multiple output voltages supported: -3.3V, 3.0V, 2.5V and 1.8V Variety of industry-standard packages

APPLICATIONS LAN switches and hubs Broadband infrastructure Industrial and medical equipment Automotive in-dash electronics Consumer electronic products

 

Cypress Semiconductor / SSCG