Title :
X-Press: Two-Stage X-Tolerant Compactor With Programmable Selector
Author :
Rajski, Janusz ; Tyszer, Jerzy ; Mrugalski, Grzegorz ; Cheng, Wu-Tung ; Mukherjee, Nilanjan ; Kassab, Mark
Author_Institution :
Mentor Graphics Corp., Wilsonville
Abstract :
This paper presents X-Press - a new two-stage test-response compactor that can be easily integrated with a multiple scan-chain environment. This compactor preserves all benefits of spatial compaction and offers, due to its overdrive sequential section, compression much higher than the ratio of scan chains to compactor outputs. X-Press is also capable of handling a wide range of unknown (X) state profiles by deploying a two-level scan-chain-selection mechanism. In addition to a new compactor architecture, original contributions of this paper include a detailed analysis of two-level error masking caused by X states and a new algorithm to both rank scan chains and then to determine, in per-pattern mode, scan-chain-selection rules used to suppress X states. Experimental results obtained for a variety of designs show feasibility and efficiency of the proposed compaction scheme, altogether with actual impact of X states on a test-pattern count. Finally, diagnostic capabilities of the proposed scheme accompanied by further experimental results are also analyzed.
Keywords :
fault diagnosis; logic testing; X-press; logic testing; per-pattern mode; programmable selector; scan chain selection; spatial compaction; test pattern count; two-level error masking; two-stage x-tolerant compactor; Fault diagnosis; fault diagnosis; scan chain selection; scan-based designs; scan-chain selection; test response compaction; test-response compaction; unknown (X) states; unknown states;
Journal_Title :
Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on
DOI :
10.1109/TCAD.2007.907276