EMI reduction by resonant clock distribution networks

In today´s automotive vehicles, electromagnetic interference (EMI) from electronic circuits has become a serious concern. The discussion in this paper proves that a clock signal generated by a resonant clock distribution network exhibits better EMI performance compared to that of a conventional buffer-driven clock network. This discussion is supported by analyzing different clock spectrums and using a simple model of simultaneous switching noise (SSN). According to simulation results presented in a 90-nm CMOS process, using a sinusoidal clock instead of a trapezoidal one, the magnitude of the first tone in the spectrum of SSN is reduced at least by 6.7 dB.