A stochastic model of digital switching noise

Abstract

In fully CMOS digital integrated systems, switching activity of logic gates is the source of the so-called "digital noise". Together with interconnections parasitics, digital switching noise is known to cause "bouncing" effects, i.e. oscillations of on-chip supply and bias voltages, which can remarkably degrade overall system performance. Digital switching is a completely deterministic process, depending on both circuit parameters and input signals. However, the huge number of logic blocks in a digital integrated system makes digital switching a cognitively stochastic process. Therefore, logic transition activity can be analyzed using a stochastic approach. In this paper, we model the digital switching current as a stationary shot noise process, and we derive both its amplitude distribution and its power spectral density.