Boundary-Functional Broadside and Skewed-Load Tests

摘要

Close-to-functional broadside tests are used for avoiding overtesting of delay faults that can result from nonfunctional operation conditions, while avoiding test escapes because of faults that cannot be detected under functional operation conditions. When a close-to-functional broadside test deviates from functional operation conditions, the deviation can affect the entire circuit. This article defines the concept of a boundary-functional broadside test where non-functional operation conditions are prevented from crossing a pre-selected boundary. Using the procedure described in this article, the boundary maintains the same values under a boundary-functional broadside test as under a functional broadside test from which it is derived. Indirectly, this ensures that the deviations from functional operation conditions throughout the entire circuit are limited. The concept of a boundary-functional broadside test is extended to skewed-load tests, and to partial-boundary-functional tests. Experimental results are presented for benchmark circuits to demonstrate the fault coverage improvements that can be achieved using boundary-functional broadside and skewed-load tests as well as partial-boundary-functional tests of both types.