THE IMPACT OF SIGNAL TRANSITION TIME ON PATH DELAY COMPUTATION

It has been recognized for some time that nonzero signal rise and fall times contribute to gate propagation delays. Practically, however, mo st timing analysis tools ignore these contributions when computing pat h delays and identifying critical paths in combinational circuits. In this paper we describe how these rise and fall times can be incorporat ed into path analysis algorithms. Interestingly, we show that signal t ransition time information can be accounted for in a simple and effici ent preprocessing step followed by the application of standard path an alysis methods. This two-step approach is shown to predict path delays with sufficient accuracy without unnecessarily complicating path anal ysis.