Test Methodology for Dual-rail Asynchronous Circuits

Abstract

With low power and variation-tolerant features, asynchronous have been widely used in advanced VLSI designs. Testing asynchronous circuits has become a very important practical issue. This research presents new test methodology, including design for testability (DFT) and automatic test pattern generation (ATPG), for asynchronous dual-rail circuits. The proposed DAC-scan cell is a hazard-free scan design, which can be applied to various implementations of dual-rail asynchronous circuits. Two-pattern stuck-at test and three-pattern delay test techniques are presented to detect local feedback faults in the circuits without inserting extra DFT into feedback loops. With our test methodology, we can use traditional full-scan ATPG to generate high fault coverage test patterns. Moreover, designers can tradeoff between fault coverage and area overhead by using different versions of DAC-scan cells.