A hybrid scheme for compacting test responses with unknown values
Mango C.-T. Chao, Kwang-Ting Tim Cheng, Seongmoon Wang, Srimat Chakradhar, Wenlong Wei · Digest of technical papers/Digest of technical papers - IEEE/ACM International Conference on Computer-Aided Design · 2007
This paper presents a hybrid compaction scheme for test responses containing unknown values, which consists of a space compactor and an unknown-blocking Multiple Input Signature Registers (MISR). The proposed scheme guarantees no coverage loss for the modeled faults. The proposed hybrid scheme can also be tuned to observe any user- specified percentage of responses for controlling the coverage loss for un-modeled faults. The experimental results demonstrate that, in comparison with a space compactor or an unknown-blocking MISR alone, the hybrid compaction scheme achieves a lower coverage loss without demanding more test-data volume. In addition, we propose a quantitative approach to estimate the required percentage of observable responses for the proposed scheme, directly based on a test-quality metric of un-modeled faults.