On the detection of path delay faults by functional broadside tests

Abstract

Paths that cannot be sensitized during functional operation do not need to be optimized for speed, and their delays may be higher than the clock period. This paper uses functional broadside tests for path delay faults in order to avoid overtesting due to the detection of faults that are associated with such paths. To ensure that as many small delay defects as possible will be detected, the paper considers path delay faults that are associated with full paths as well as ones associated with subpaths. It uses a type of path delay faults called transition path delay faults to define the conditions under which a path delay fault associated with a subpath is detected. It uses detection conditions called the hazard-based detection conditions, which yield a type of weak non-robust tests, to detect as many transition path delay faults as possible. Experimental results demonstrate the importance of considering subpaths for different coverage objectives.