The AC strength of a pattern generator is the fraction of the exhaustive two-pattern count that it can apply to the logic given sufficient time. It is a measure that allows assessing how well a pattern generator can serve in applying AC test vectors to the logic. Generators with high AC strengths tend to perform better than generators with low AC strengths. Special generators with high AC strengths can be designed with a considerable penalty of hardware overhead. An alternative to designing special pattern generators that can serve well during AC test is to separate the inputs of the logic fed by the generator, so that no two inputs belonging to the same output cone in the logic are connected to adjacent stages of the generator. This input separation will facilitate an effective AC test, and will not suffer from the high overhead that the special generators suffer from. This paper introduces the notion of the AC strength of a pattern generator and proposes the input separation scheme that will allow an efficient AC test to be performed on the logic.
All Science Journal Classification (ASJC) codes
- Electrical and Electronic Engineering
- AC test
- level sensitive scan design
- scan path
- test pattern generator