Test Point Insertion with Control Point by Greater Use of Existing Functional Flip-Flops

Abstract

This paper presents a novel test point insertion (TPI) method for a pseudo‐random built‐in self‐test (BIST) to reduce the area overhead. Recently, a new TPI method for BISTs was proposed that tries to use functional flip‐flops to drive control test points instead of adding extra dedicated flip‐flops for driving control points. The replacement rule used in a previous work has limitations preventing some dedicated flip‐flops from being replaced by functional flip‐flops. This paper proposes a logic cone analysis–based TPI approach to overcome the limitations. Logic cone analysis is performed to find candidate functional flop‐flops for replacing dedicated flip‐flops. Experimental results indicate that the proposed method reduces the test point area overhead significantly with minimal loss of testability by replacing the dedicated flip‐flops.