Test set embedding for deterministic BIST using a reconfigurable interconnection network

We present a new approach for deterministic built-in self-test (BIST) in which a reconfigurable interconnection network (RIN) is placed between the outputs of a pseudorandom pattern generator and the scan inputs of the circuit under test (CUT). The RIN, which consists only of multiplexer switches, replaces the phase shifter that is typically used in pseudorandom BIST to reduce correlation between the test data bits that are fed into the scan chains. The connections between the linear-feedback shift-register (LFSR) and the scan chains can be dynamically changed (reconfigured) during a test session. In this way, the RIN is used to match the LFSR outputs to the test cubes in a deterministic test set. The control data bits used for reconfiguration ensure that all the deterministic test cubes are embedded in the test patterns applied to the CUT. The proposed approach requires very little hardware overhead, only a modest amount of CPU time, and fewer control bits compared to the storage required for reseeding techniques or for hybrid BIST. Moreover, as a nonintrusive BIST solution, it does not require any circuit redesign and has minimal impact on circuit performance.