A selective X-masking for test responses in the presence of unknown values
Xu Shubing, Taweesak Reungpeerakul · 2011
As the unknown values (X's) appear in the output response, a large amount of scan cells may not be observed during test. In this paper we present a flexible X-masking logic called selective X-masking to handle the majority of X's, while the X-tolerant compactor is applied to handle the remained X's. The objective of this approach is to improve the observability of the test responses. The results show that this scheme can achieve a significant improvement of observability for output responses and reduce significantly the data overhead of the X-masking.