Substituting Transition Faults with Path Delay Faults as a Basic Delay Fault Model

Comparing a single transition fault with a single path delay fault, targeting (i.e., simulating or generating a test for) a path delay fault is not more complex than targeting a transition fault. However, targeting a set of path delay faults is significantly more complex than targeting a set of transition faults when the goal is to consider the testable path delay faults that are associated with the longest paths. The reason is the large fraction of untestable path delay faults among these faults. This complication is removed if the requirement on the lengths of the paths is removed. In this case, it is possible to use path delay faults instead of transition faults as a basic delay fault model for better coverage of small delay defects. This paper studies the effects of using path delay faults as a basic delay fault model instead of transition faults.