Path delay fault testing of multiplexer-based shifters

In this paper we present a method for path delay fault testing of multiplex er-based shifters. We show that many paths of the shifter are not single pa th propagating hazard free robustly testable (SPP-HFRT) and we present a pa th selection method such that all the selected paths are SPP-HFRT by (O log (2) n) test-vector pairs, where n is the length of the shifter's operand. T he propagation delay along all other paths is a function of the delays alon g the selected paths. This is the first work addressing the problem of shif ter path delay fault testing.