Selecting Close-to-Functional Path Delay Faults for Test Generation

A large number of paths necessitates the selection of path delay faults for test generation. The selected path delay faults should be detectable, and associated with the longest paths of the circuit. This paper introduces a new consideration that is important for the selection of path delay faults, namely, the extent to which a path delay fault can be activated during functional operation. This is important since certain paths that cannot be activated during functional operation may not be optimized for speed. To address this issue, the paper describes a path selection procedure that uses functional broadside tests to identify functional path delay faults. The procedure selects target path delay faults that are associated with the longest paths, and are as similar as possible to functional path delay faults. Experimental results for benchmark circuits demonstrate the levels of similarity.