FA-STAC: A Framework for Fast and Accurate Static Timing Analysis with Coupling

Abstract

Abstract-This paper presents a framework for fast and accurate static timing analysis considering coupling. With technology scaling to smaller dimensions, the impact of coupling induced delay variations can no longer be ignored. Timing analysis considering coupling is iterative, and can have considerably larger run-times than a single pass approach. We propose a novel and accurate coupling delay model, and present techniques to increase the convergence rate of timing analysis when complex coupling models are employed. Experimental results obtained for the ISCAS benchmarks show promising accuracy improvements using our coupling model while an efficient iteration scheme shows significant speedup (up to 62.1%) in comparison to traditional approaches.

NostraXtalk

“…Rise and fall delay windows on net I1 are [2,4] and [2.5,3.5]. Similarly on net I2 the windows are [3,5] and [3.5,4.5]. G1 and G2 are inverters of different sizes which leads to different timing arcs arc1 and arc2 in them.…”

“…Also assume that net I1 and I2 has similar rise and fall slew windows given by [0.2,0.6] and [0.4,0.8]. Such delay and slew windows are obtained from a timing flow as presented in [5]. Note the difference of our notations from prevalent conditions.…”

“…We define a timing event as an ordered pair of arrival time and slew. Consider a coupling model based on slew and arrival times recently proposed by [5]. Assuming delay on arc1 due to input rise slew as 0.6 and loading cap of C 1 g +Cc be 0.8.…”

Pessimism Reduction in Coupling-Aware Static Timing Analysis Using Timing and Logic Filtering

“…[8] presented an iterative static timing analysis algorithm based on some initial switching windows (best case crosstalk delays as opposed to worst case crosstalk delays considered by [6]) and iteratively updating the timing information until convergence. Though [8] used a novel coupling model in timing analysis based on arrival and transition times, they did not explore the model dynamics which, as we show, turns out to be a key factor in coupling-aware static timing analysis using logic constraints. To exploit logic feasibility conditions, two recent researches proposed pessimism reduction [19], [4].…”

“…Since delay and crosstalk are inherently chicken-and-egg problem (victim delay depends on the amount of charge injected by the aggressors which in turn depends on the victim arrival times and slews), iterative methods are needed to perform coupling analysis [20], [8], [6], [3]. Zhou [20] established the theoretical foundation for the iterative analysis.…”