Buffer delay change in the presence of power and ground noise

  • Authors:
  • Lauren Hui Chen;Malgorzata Marek-Sadowska;Forrest Brewer

  • Affiliations:
  • Synopsys Inc., Mountain View, CA;Electrical and Computer Engineering Department, University of California, Santa Barbara, CA;Electrical and Computer Engineering Department, University of California, Santa Barbara, CA

  • Venue:
  • IEEE Transactions on Very Large Scale Integration (VLSI) Systems - Special section on the 2001 international conference on computer design (ICCD)
  • Year:
  • 2003

Quantified Score

Hi-index 0.00

Visualization

Abstract

Variations of power and ground levels affect very large scale integration circuit performance. Trends in device technology and in packaging have necessitated a revision in conventional delay models. In particular, simple scalable models are needed to predict delays in the presence of uncorrelated power and ground noise. In this paper, we analyze the effect of such noise-on-signal propagation through a buffer and present simple, closed-form formulas to estimate the corresponding change of delay. The model captures both positive (slowdown) and negative (speedup) delay changes. It is consistent with short-channel MOSFET behavior, including carrier velocity saturation effects. An application shows that repeater chains using buffers instead of inherently faster inverters tend to have superior supply-level-induced jitter characteristics. The expressions can be used in any existing circuit performance optimization design flow or can be combined into any delay calculations as a correction factor.