Checking delay-insensitivity: 10⁴ gates and beyond

Wire and gate delays are accounted to have equal, or nearly equal, effect on circuit behavior in modern design techniques. This paper introduces a new approach to verifying circuits whose behavior is independent of component delays (delay-insensitive). It shows that for a particular way of implementing a delay-insensitive circuit, through a Null Convention Logic methodology, the complexity of the verification task might be significantly reduced. This method is implemented using Satisfiability (SAT) solvers and is successfully tested on realistic design examples having tens of thousands of gates.