Weighted pseudorandom generation for built-in self-test

A novel method to obtain weights for weighted pseudorandom built-in self-test (BIST) techniques that can be used to solve the fault coverage problems posed by hard-to-detect faults is presented. In the method, weights are directly obtained by means of the stuck-at fault simulation instead of using testability measures. In this way, a single set of weights is obtained that is more conveniently implemented than the multiple distributions provided by alternative techniques. Results obtained on benchmark circuits show a large increase of the achieved fault coverage values compared with the case of uniformly biased pseudorandom sequences