ALAPTF: a new transition fault model and the ATPG algorithm

The work presents a new transition fault model called as late as possible transition fault (ALAPTF) model. The model aims at detecting smaller delays, which be missed by both the traditional transition fault model and the path delay model. The model makes sure that each transition is launched as late as possible at the fault site, accumulating the small delay defects along its way. Because some transition faults may require multiple paths to be launched, the simple path-delay model miss such faults. Results on ISCAS'85 and ISCAS'89 benchmark circuits shows that for all the cases, the new model is capable of detecting smaller gate delays and produces better results in case of process variations. For all circuits, on an average, 30% of the time the transition reaches later than traditional models. The algorithm proposed also detects robust and non-robust paths along with the transition faults and the execution time is linear to the circuit size.