A fast optimal robust path delay fault testable adder

In this paper we explore the test complexity of the adder function with respect to the robust path delay fault model. A lower bound of ω(n²) for the cardinality of a complete test set for a combinational n-bit adder is proven. This result is valid for any adder design known until now. In addition we present a fast O(√n)-time adder that is fully robust path delay fault testable with a test set of size Θ(n²)