Encounter test OPMISR/sup +/ on-chip compression

As technology progresses, chips push on all automated test equipment (ATE) cost variables: speed, pin count, and test buffer size. In response to the challenges of testing these ever-larger chips, all of the major ATPG vendors have come out with products that compress test data volume and reduce test time - OPMISR: simple, effective output compression. While OPMISR can provide a substantial data volume reduction, it is limited to about 50% reduction in test application time. An alternative implementation of OPMISR, OPMISR⁺, was being employed at the Cadence Encounter Test product. OPMISR⁺ can easily provide greater than 100 times test data volume reduction in addition to 40 times or more scan test time reduction. This paper gives an example of its scan configuration