What is Scan compression?

Scan compression is a technique used in integrated circuit testing to reduce the amount of test data and the test application time. It involves modifying the scan chains in a design to minimize the number of scan flip-flops that need to be controlled and observed during testing. This is achieved by encoding the test vectors, which significantly reduces the size of the test data that needs to be stored and applied. This also decreases the time required to apply the test, leading to lower testing costs.