Test scheduling for built-in self-tested embedded SRAMs with data retention faults

Abstract

The test scheduling problem for built-in self-tested embedded SRAMs (e-SRAMs) when data retention faults (DRFs) are considered is addressed here. We proposed a 'retention-aware' test power model by taking advantage of the fact that there is near-zero test power during the pause time for testing DRFs. The proposed test scheduling algorithm then utilises this new test power model to minimise the total testing time of e-SRAMs while not violating given power constraints, by scheduling some e-SRAM tests during the pause time of DRF tests. Without losing generality, we consider both cases where the pause time for DRFs is fixed and cases where it can be varied. Experimental results show that the proposed 'retention-aware' test power model and the corresponding test scheduling algorithm can reduce the testing time of e-SRAMs significantly with negligible computational time.