Analysis and design of regular structures for robust dynamic fault testability

The authors analyze various regular structures such as adders, arithmetic logic units, comparators, multipliers, and parity generators to determine if they are testable for dynamic faults, or how they can be modified to be testable for dynamic faults while still maintaining good area and performance characteristics. In addition to minimizing the area and delay, another key consideration is to get designs which can be scaled to an arbitrary number of bits while still maintaining complete testability. In each case, the emphasis is on obtaining circuits which are fully path-delay-fault testable. In the process of design modification to produce fully robustly testable structures, the authors derive a number of new composition rules that allow cascading individual modules while maintaining robust testability under dynamic fault models. Where complete robust path-delay-fault testability is not achievable without significant area or speed penalties, methods of obtaining circuits that are fully testable in weaker fault models, such as transistor stuck-open-fault and robust gate-delay-fault, are analyzed