Test pattern generation for width compression in BIST

The main objectives of built-in self test (BIST) are the design of test pattern generator circuits which achieve the highest fault coverage, require the shortest sequence of test vectors and utilize the minimum circuit area. This paper targets the problem of generating test patterns for stuck-at faults that induce compatibility relations between the primary inputs of the circuit under test. These compatibility relations can be used for designing counter-based test generator circuits with a reduced number of bits, thus requiring smaller testing time and smaller area. The proposed solution is based on an integer linear programming (ILP) formulation that builds on existing propositional satisfiability (SAT) models for test pattern generation. An ATPG tool for minimum test pattern generation for width compression (MTP-C) is described, which illustrates the practical applicability of our approach for a wide range of benchmark circuits