Summary
International Symposium on Electromagnetic Compatibility
2009
Session Number:22Q1
Session:
Number:22Q1-2
Experimental Study of IC EMI Reduction by Spreading Clock-Signal Spectrum
C. H. Huang, M. S. Lin, C. I. G. Hsu, H. C. Hsieh,
pp.281-284
Publication Date:2009/7/20
Online ISSN:2188-5079
Summary:
Clock circuits have been considered as major sources of EMI from an IC. Hence, the reduction of EMI from clock circuits has been an active research topic in recent years. In this study, a spread spectrum technique was employed to modulate clock signals so as to reduce the EMI level. A TI-offered evaluation board containing a TI CDCE906 clock synthesizer with a built-in FM triangular modulating function was used as the spread spectrum clock generator (SSCG). The output spectrum-spread clock (SSC) was in turn fed into a PIC18F4420 microchip test board. With the clock signal frequency modulated and the rise/fall time extended, measured results revealed that the emission levels of the microchip test board can be greatly reduced.