A Hybrid Dictionary Test Data Compression for Multiscan-Based Designs

Youhua SHI  Shinji KIMURA  Masao YANAGISAWA  Tatsuo OHTSUKI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E87-A   No.12   pp.3193-3199
Publication Date: 2004/12/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
Category: Test
test data compression,  test slice,  multiple scan chain,  ATE,  

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In this paper, we present a test data compression technique to reduce test data volume for multiscan-based designs. In our method the internal scan chains are divided into equal sized groups and two dictionaries were build to encode either an entire slice or a subset of the slice. Depending on the codeword, the decompressor may load all scan chains or may load only a group of the scan chains, which can enhance the effectiveness of dictionary-based compression. In contrast to previous dictionary coding techniques, even for the CUT with a large number of scan chains, the proposed approach can achieve satisfied reduction in test data volume with a reasonable smaller dictionary. Experimental results showed the proposed test scheme works particularly well for the large ISCAS'89 benchmarks.