Sequential test generation with reduced test clocks for partial scan designs

Partial scan design technique is often preferred to full scan because the use of smaller number of scan flip-flops leads to less performance degradation and less overhead. However, the number of clocks required to apply a test vector is proportional to the number of flip-flops in the scan path whenever scan is performed. This tends to increase the test application considerably. In this paper we presents an algorithm to generate a test with fewer test clocks for partial scan designs by using sequential test generation and scan strategies. The objective is to find a test that requires less test clocks while achieving high fault coverage. The algorithm, Test Application time Reduction for Partial scan design (TARP), is implemented and tested on a set of ISCAS sequential benchmark circuits. The algorithm produces a test with substantial reduction in the number of test clocks, compared to a test in which each test vector is associated with a scan operation.>