Path-oriented transition fault test generation considering operating conditions

We describe a test generation procedure for path-oriented transition faults that takes into account the fact that operating conditions may change during circuit operation. A path-oriented transition fault is detected through the longest sensitizable path that goes through the fault site. The operating conditions we consider are junction temperature and power supply voltage. Since path delays change with operating conditions, the longest path through a fault site may be different under different conditions. We show that test generation using nominal delays is not sufficient for covering the complete range of operating conditions, even if N-detection test generation is used. Therefore, operating conditions need to be addressed explicitly during test generation. However, since temperature and voltage are continuous variables and represent an infinite number of values in the range, test generation must concentrate on a small selected set of operating conditions. We discuss the selection of these conditions and demonstrate that N-detection test generation with multiple operating conditions is effective in covering the range of operation conditions almost completely.