The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 07, 2011
Filed:
Sep. 30, 2008
Peter Wohl, Williston, VT (US);
John A. Waicukauski, Tualatin, OR (US);
Frederic J. Neuveux, Meylan, FR;
Yasunari Kanzawa, Sunnyvale, CA (US);
Peter Wohl, Williston, VT (US);
John A. Waicukauski, Tualatin, OR (US);
Frederic J. Neuveux, Meylan, FR;
Yasunari Kanzawa, Sunnyvale, CA (US);
Synopsys, Inc., Mountain View, CA (US);
Abstract
To increase scan compression during testing of an IC design, an X-chain method is provided. In this method, a subset of scan cells that are likely to capture an X are identified and then placed on separate X-chains. A configuration and observation modes for an unload selector and/or an unload compressor can be provided. The configuration and observation modes provide a first compression for non-X-chains that is greater than a second compression provided for X-chains. ATPG can be modified based on such configuration and observation modes. This X-chain method can be fully integrated in the design-for-test (DFT) flow, requires no additional user input, and has negligible impact on area and timing. Test generation results on industrial designs demonstrate significantly increased compression, with no loss of coverage, for designs with high X-densities.