BCH-based Compactors of Test Responses with Controllable Masks

This paper presents a novel approach to compacting test response results for a multiple scan chains design. The compactors are based on (n+1, k) extended BCH code and guarantee detecting up to 2t single-bit errors and any odd number of single-bit errors, where n, k, t are integers depending on the particular BCH code used. Another technique uses controllable masks to handle any number of X´s on test responses. The techniques have ability to detect more single-bit errors with minimum numbers of compactor outputs and can be used to reduce tester channels, test application time, and test data volume, independent of circuit under test (CUT) and fault models