New BIST techniques for universal and robust testing of CMOS stuck-open faults

Abstract

This paper presents three built-in self-test (BIST) schemes for robust testing of stuck-open faults in combinational FCMOS complex cells of arbitrary structure. The first method shows that all single stuck-open faults can be robustly tested by applying a universal sequence of 5/spl times/2/sup n/ vectors to the modified circuit under test (CUT), and counting the number of 1's in the output response. The second method uses the same test pattern generator (TPG), but faults are detected by a self comparison technique without the need of storing a signature. Finally, we propose a new adaptive BIST technique, where the TPG is driven by the past outputs of the CUT itself In all the cases, the TPG is universal, i.e., if does not depend on the functionality and the structure of the CUT, but does ensure robust testing. Neither any test vector, nor any fault dictionary, is required. These approaches provide simplicity, less testing time and test data, and compare favorably with earlier BIST designs for CMOS circuits.