Detection of Delay Faults in Memory Address Decoders

In this paper we present an efficient test concept for detection of delay faults in memory address decoders based on the march test tactic. The proposed Transition Sequence Generator (TSG) generates an optimal transition sequence for sensitization of the delay faults in address decoders by Hayes's transformation on a reflected Gray code. It can be used for parallel Built-In Self-Testing (BIST) of high-density RAMs. We also present an efficient Design For Test (DFT) approach for immediate detection of the effects of the delay faults in the address decoders which does not change memory access time. It requires extra logic to be attached to the outputs of the address decoders. This DFT approach can be used to increase memory testability for both on-line and off-line testing of single- and multi-port RAMs.