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.

Date of Patent:
Sep. 15, 1998

Filed:

Oct. 31, 1996
Applicant:
Inventors:

Saiid Rezvani, Los Gatos, CA (US);

Anh Nguyen, Santa Clara, CA (US);

Assignee:

Altera Corporation, San Jose, CA (US);

Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
G06K / ; G11B / ;
U.S. Cl.
CPC ...
371-1 ; 371 62 ;
Abstract

A method of operating electronic device test equipment in accordance with a known overall timing parameter includes the step of identifying a first set of time delays between a first set of electrically shorted test pads. A second set of time delays is measured between a second set of electrically shorted test pads. A bridge time delay is then obtained between a third set of electrically shorted test pads; the third set of electrically shorted test pads is selected such that the third bridge time delay characterizes the timing relationship between the first set of time delays and the second set of time delays. A clock reference edge is then defined. Skew values are then generated based upon the first set of time delays, the second set of time delays, the bridge time delay, and the clock reference edge. An overall tester accuracy value is calculated from the most negative skew value and the most positive skew value of the skew values. A functional device guard band is then defined with respect to the overall tester accuracy value. Thereafter, the electronic device test equipment is operated to identify tested electronic devices that do not function within the functional device guard band. The overall tester accuracy value may also be compared to an accuracy threshold value. Calibration operations are performed on the electronic device test equipment when the overall tester accuracy value exceeds the accuracy threshold value.


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