Optimizing the P/N ration for balanced rise/fall delays Your goal in this step is to use HSPICE to find the optimal (P/N) ratio that produces the ideal LO-skew, and the ideal HI-Skey inverters. Recall that a LO-skew logical gate is a gate where the transition from HI-t-to-LO is twice as fast as the transition from LO-to-HI. In other words, the propagation delay in the former is half the propagation delay in the latter transition