A diagnosis method using pseudo-random vectors without intermediate signatures

A diagnosis method is proposed which may be used to locate faults in circuits tested with random or pseudorandom test vectors. No intermediate signatures are involved, and the external hardware required is not complex. This proposed diagnosis scheme, called DAPPER, is applicable to multioutput combinational circuits. DAPPER classifies faults initially by their detection probability for coarse resolution, and secondly using their first failing pattern and a conventional signature for fine resolution. This method uses offline posttest simulation to isolate a single fault with only a fraction of the simulation that would ordinarily be required. Additionally, any failures within the test hardware itself may be diagnosed using the method.<>