Ronald E Todd

US Patent:

6883113, Apr 19, 2005

Filed:

Apr 18, 2002

Appl. No.:

10/125900

Inventors:

Bruce McWilliam - Manassas VA, US
Ronald Todd - Amissville VA, US
Thomas M. Storey - Manassas VA, US

Assignee:

Bae Systems Information and Electronic Systems Integration, Inc. - Manassas VA

International Classification:

G06F011/00

US Classification:

714 17, 714 29, 714 30, 714 35, 714 37, 324763, 324764, 324765

Abstract:

A procedure for temporally isolating an environmentally dependent integrated circuit fault includes the steps of determining a marginally failing and a minimally passing environmental condition corresponding to the fault; identifying a clock cycle Tat which the fault was first detected; determining a candidate clock cycle at which the fault may have occurred; and iteratively a) applying test pattern subsets from an initial clock cycle through the candidate clock cycle under the marginally failing environmental condition; b) applying remaining test patterns under the minimally passing environmental condition; and c) adjusting the candidate clock cycle based upon whether the fault occurred during test pattern subset application up through the candidate clock cycle under the marginally failing environmental condition. Candidate clock cycle adjustment in accordance with a binary search technique enables determination of an exact clock cycle at which the fault occurred in a maximum of Log(T+1) iterations.