Enhanced launch-off-capture transition fault testing

A novel scan-based at-speed test is proposed in which a transition can be launched either from the scan path or the functional path. The technique improves the controllability of transition fault testing and it does not require the scan enable to change at-speed. The scan enable control information is encapsulated in the test data and transferred during the scan operation to generate the local scan enable signals during the launch and capture cycle. A new scan cell, referred to as local scan enable generator (LSEG), is inserted in the scan chains to generate the local scan enable signals. The proposed technique is robust, practice-oriented and suitable for designs targeted for very low cost ATEs