Comparison and Impact of Substrate Noise Generated by Clocked and Clockless Digital Circuitry

摘要

A pseudo-random number generator implemented in asynchronous logic generates one-fifth the RMS substrate noise compared to the equivalent design in synchronous logic. An asynchronous 8051 processor generates one-third the RMS substrate noise as the equivalent synchronous design. The SNR of a second order delta-sigma modulator (DSM) is not affected by substrate noise due to an asynchronous processor while it experiences 15 dB degradation when the synchronous 8051 processor is clocked near integer multiples of the DSM sampling frequency