Spread spectrum clock generation for reduced electro-magnetic interference in consumer electronics devices

For better electro-magnetic interference (EMI) reduction with minimum hardware increase, a sawtooth dualtone modulation profile has been applied to spread spectrum clock generation (SSCG) phase locked loop (PLL). The SSCG PLL implemented in a 0.18μm CMOS process shows the 23.8dB EMI reduction. This result shows that proposed modulation profile provides 3.5dB better EMI reduction with 39% increased hardware than the conventional triangular modulation profile. For fair comparison of various modulation profiles, a figure of merit (FoM) is introduced and the proposed one shows the best FoM among various modulation profiles.