A novel BIST scheme for reducing the test storage( TS) is presented. The proposed approach relies on a two-dimensional compression scheme,which combines the advantages of the previous LFSR reseeding scheme and test set embedding technique based on ring counters( RCs) to improve the encoding efficiency. It presents a general method to determine the probability of encoding as a function of the number of specified bits in the test cube,the length of the LFSR and the width of the test set,and conclude that the probability of encoding a n-bit test cube with s specified bits using a( smax+ 1 + 20 / n)-stage LFSR with a fixed polynomial is1- 10-6. Experimental results for the ISCAS '89 benchmark circuits show that compared with the previous schemes,the proposed scheme based on LFSR-RC reseeding requires 57% less TS and 99. 1% test application time( TAT) with simple and uniform BIST control logic.
