On the application of local circuit transformations with special emphasis on path delay fault testability

Several types of local transformations and their effect on path delay fault testability have been examined in the literature. In this paper we present SALT (System for Application of Local Transformations), which is a general tool for the application of a user-defined set of local transformations. The concepts of "related transformations" and of "pseudo-isomorphism" are introduced, which are used in SALT to allow the application of local transformations more frequently. We use SALT to apply testability preserving and testability improving transformations. The effect of these transformations on the size, depth and testability of the transformed circuits is compared to the results obtained by other approaches on benchmark circuits.