A novel approach for test data volume reduction with multiple scan chains

Test technique with multiple scan chains can fully reduce test time, but more data input channels, higher hardware overhead, lower test data compression ratio and lower fault coverage along with it are all paid more extensive attention to in the current test field. A cyclic shift compression technique is proposed and applied to multiple scan chain testing. Unlike general shift, cyclic shift technique can not only retain the don´t bits in original test vectors, but also increase the correlation between vectors. T he experiment results and analysis demonstrate that the proposed approach can maintain the advantages of multiple scan chain testing and transmit data using single channel, further improve test compression ratios and meet the needs of full fault test and hybrid built-in self test with lower hardware cost.