Timing Analysis using Functional Relationships

The usual block oriented timing analysis for logic circuits does not take into account functional relations between signals. If we take functional relations into consideration we may find that a long path is never activated. This observation can be used to calculate improved and more accurate delays. It is not practical to consider the complete truth table with all the relationships between signals. We use a procedure that considers only a subset of the relationships between signals and checks for non-functional paths. The delay calculation then takes into account the discovered non-functional paths to determine less pessimistic delays through the logic.