Propagation Delay Estimation for Mixed-Signal Modeling of Comparators

With higher complexity of mixed-signal circuits the amount of interfaces between digital and analog circuitry is increasing. The verification of the correct interaction at those interfaces is a key task to the mixed-signal verification process. Creating models of comparators is a significant subject because they are not only part of those interfaces but also realize the domain crossing from analog to digital simulation engine. Beside offset or hysteresis, the propagation delay is one of the most critical properties to be considered in a comparator model. Usually the propagation delay is only modeled as a static transportation delay. This contribution presents a method for characterization and efficient modeling of the propagation delay in dependence of the dynamical behavior of the input signal as well as other operating conditions which is independent of the chosen topology. The proposed method is suitable for different system-level modeling approaches including electrical as well as real number modeling and its feasibility is demonstrated in a case study.