Test-point insertion to enhance test compaction for scan designs

Test compaction procedures to reduce the test application time for scan designs terminate when they cannot reduce the test application time without reducing the fault coverage. We propose a procedure for placing observation points that allows higher levels of compaction to be achieved without loss of fault coverage. The observation point values are read only at the last time unit of every test, and therefore, they can be scanned-out at the same time as the next-state values