Classification and test generation for path-delay faults using single stuck-fault tests

In this paper, we classify path-delay faults into three categories: singly-testable (ST), multiply-testable (MT), and singly-testable dependent (ST-dependent). All ST faults are guaranteed detection in the case of a single fault, and some may be guaranteed detection through robust and validatable non-robust tests even in the case of multiple faults. An ST-dependent fault can affect the circuit speed only if certain ST faults are present. Thus, if the ST faults are tested, the ST-dependent faults need not be tested. MT faults cannot be guaranteed detection, but affect the speed only if delay faults simultaneously exist on a set of paths none of which is ST. We classify all path-delay faults into the three categories by a procedure using any unaltered single stuck fault test generation tool. We use only two runs of this tool on a network derived from the original network. As a by-product of this process, we generate single and multiple input change delay tests for all testable faults. With these tests, we expect that most defective circuits are identified. Examples and results on ISCAS´89 benchmarks are presented