Multiple stuck-at fault testability of a combinational circuit derived by covering ROBDD nodes by Invert-And-Or sub-circuits

Multiple stuck-at fault testability becomes very important for high performance circuits. Combinational circuits derived by covering ROBDD nodes by Invert-And-Or sub-circuits are considered. Their multiple stuck-at fault (MSAF) testability is set up. It is shown that a test for single stuck-at faults (SAFs) at input and output poles of sub-circuits coincides with the test for multiple stuck-at faults (MSAFs) at poles of any set of sub-circuits under condition that test patterns are delivered to the circuit in the determined order. MSAFs test length is not more than 4N, where N is the number of internal nodes of ROBDDs describing a circuit behavior.