The application of single input change (SIC) pairs of test patterns is very efficient for sequential, i.e. stuck-open and delay fault testing. In this paper a novel implementation for the application of SIC pairs is presented and a formal proof of its completeness is provided. The presented generator is optimal in time, in the sense that it generates the n-bit SIC pairs in time
, i.e. equal to the theoretical minimum. Comparisons with the schemes that have been proposed in the open literature that generate SIC pairs in optimal time, reveal that the proposed scheme requires less hardware overhead.