Structural delay testing of latch-based high-speed pipelines with time borrowing

Abstract

High-speed circuits use latch-based pipelines in some of their most delay-criticalparts. The use of latches not only allows attainment of high clock rate but also enables attainment of high yield at desired clock rate by permitting unintentional time borrowing. In this paper, we first demonstrate that none of the existing design-for-testability (OFT) techniques can be used to simplijj delay testing of such circuits. We then demonstrate that this leads to very high test generation and test application times. In many circuits, very low path delay fault coverage is obtained. We then propose a systematic test approach and associated DFT that significantly reduces the test generation and test application costs, and, for many circuits, significantly increases path delay fault coverage.