A beta model for estimating the testability and coverage distributions of a VLSI circuit

Abstract

A relation between fault coverage and testability is employed to predict population coverage. The testability profile is modeled as a mixture of a discrete impulse function and a continuous beta distribution. The parameters of the modeled distribution are estimated from fault coverage data obtained on a sample of faults. The beta distribution is chosen due to its flexible nature. The computed values of the beta parameters are dependent on the distribution of input vectors. Experimental results on three of the large ISCAS-89 circuits reflect the accuracy of the estimated fault coverage. Applications of the presented work include test generation by fault sampling, testability estimation, and test length predictions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>