Body-voltage estimation in digital PD-SOI circuits and its application to static timing analysis

Partially depleted silicon-on-insulator (PD-SOI) has emerged as a technology of choice for high-performance low-power deep-submicrometer digital integrated circuits. An important challenge to the successful use of this technology involves successfully managing and predicting the large “uncertainties” in the body potential and consequently the threshold voltages that can result from unknown past switching activity. In this paper, we present a unique state-diagram abstraction of the PD-SOI field-effect transistor that can capture all of the past switching activity determining the body voltage. Based on this picture, four different estimation schemes are discussed that increasingly bound floating body uncertainty based on more detailed knowledge of switching activity. Using these estimation techniques within a prototype transistor-level static timing analysis engine, we demonstrate both the accuracy of the estimation and the reduction in delay uncertainty possible with these techniques