Broad-Side Delay Test

A broad-side delay test is a form of a scan-based delay test, where the first vector of the pair is scanned into the chain and the second vector of the pair is the combinational circuit's response to this first vector. This delay test form is called “broad-side” since the second vector of the delay test pair is provided in a broad-side fashion, namely through the logic. This paper concentrates on several issues concerning broad-side delay test. It analyzes the effectiveness of broad-side delay test; shows how to compute broad-side delay test vectors; shows how to generate broad-side delay test vectors using existing tools that were aimed at stuck-at faults; shows how to compute the detection probability of a transition fault using broad-side pseudo random patterns; shows the results of experiments conducted on the ISCAS sequential benchmarks; and discusses some concerns of the broad-side delay test strategy. It is shown that the broad-side method is inferior to the skewed-load method, which is another form of scan-based transition test. There is, however, a merit in combining the skewed-load method with the broad-side method. This combined method will achieve a higher transition fault coverage than each individual method alone.