Utilizing ATE Vector Repeat With Linear Decompressor for Test Vector Compression

Previous approaches for utilizing automatic test equipment (ATE) vector repeat are based on identifying runs of repeated scan data and directly generating that data using ATE vector repeat. Each run requires a separate vector repeat instruction, so the amount of compression is limited by the amount of ATE instruction memory available and the length of the runs (which typically will be much shorter than the length of a scan vector). In this paper, a new and more efficient approach is proposed for utilizing ATE vector repeat. The scan vector sequence is partitioned and decomposed into a common sequence which is the same for an entire cluster of test cubes and a unique sequence that is different for each test cube. The common sequence can be generated very efficiently using ATE vector repeat. Experimental results demonstrate that the proposed approach can achieve much greater compression while using many fewer vector repeat instructions compared with previous methods.