Abstract
To predict the difficulty of testing a wire stuck-at fault, testability analysis algorithms provide an estimated testability value by computing controllability and observability. In all previous work, signal correlation between controllability and observability is generally ignored. As a result, the estimated value can be inaccurate. This paper discusses an efficient method to take into account signal correlation for testability analysis. Our experimental results have shown that, with little run time overhead, significant improvement of testability analysis can be achieved.