Analysis of harmonic contents of switching waveforms emitted by the ultra high speed digital CMOS integrated circuits for use in future micro/nano systems applications

In this paper we outline the influence of transistor model quality and input signal on the estimates of higher order harmonic contents of switching waveforms emitted by the high performance and low power digital integrated circuits. Accurate estimates of higher order harmonic contents are essential in the design and development of highly integrated wireless communication systems. Harmonic contents are used to design tapered buffer chains, but the design quality is influenced by the device model discontinuities. We used Cadence Spectre and Matlab to analyze the spectrum of different flip flop and latch structures. They showed steep spectrum roll-off after the knee frequency. As a concrete example, various kinds of latches and flip-flops, which have the fastest switching capability, are evaluated by using BIM3v3 and BSIM4 transistor models.