2011 Volume 8 Issue 16 Pages 1367-1373
This paper proposes a scan disabling-based BIST-aided scan test (BAST) scheme. In this scheme, a pseudo-random pattern generator(PRPG) generates test vector for each slice in multiple scan chains. Using scan disabling technique, the generated test vector is shifted into the scan chains until it is compatible with its corresponding slice for a deterministic test set with don't care bits. An automatic test equipment (ATE) only needs to store the control signals instead of test data. The proposed scheme that is based on the standard scan and uses any test set with don't care bits is widely applicable and easy to deploy. Its hardware overhead that is a PRPG, phase shifter, MISR and scan disable signal is very low. Theoretical analysis and experimental results show the proposed scheme can achieve higher compression gain compared with previous low cost scheme when care bits are few.