A special march test to detect delay coupling faults for RAMs

Abstract

This paper introduces the idea of the delay coupling faults between the memory cells and also shows a new method to integrate a test for them within march tests. March tests do not cover delay coupling faults, moreover, the correct sensitizing operation sequences are not sufficient to cover them because of the large propagation time required to affect the content of the coupled cell. To cover the delay coupling faults, a special test based on the idea of the logic state of the memory array is presented. The new and more efficient march test, called DITEC+, proves to be efficient to cover the delay coupling faults.