Multiple-capture DFT system for detecting or locating crossing clock-domain faults during self-test or scan-test
DC CAFCFirst Claim
1. An apparatus for providing ordered capture clocks to detect or locate faults within N clock domains and faults crossing any two clock domains in an integrated circuit or circuit assembly in scan-test or self-test mode, where N>
- 1, each clock domain having one capture clock and a plurality of scan cells, each capture clock comprising a plurality of capture clock pulses;
said apparatus comprising;
(a) means for generating and shifting-in N test stimuli to all said scan cells within said N clock domains in said integrated circuit or circuit assembly during a shift-in operation;
(b) means for applying an ordered sequence of capture clocks to all said scan cells within said N clock domains, the ordered sequence of capture clocks comprising at least a plurality of capture clock pulses from two or more selected capture clocks placed in a sequential order such that all clock domains are never triggered simultaneously during a capture operation; and
(c) means for analyzing output responses of all said scan cells to locate any faults therein.
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Abstract
A method and apparatus for providing ordered capture clocks to detect or locate faults within N clock domains and faults crossing any two clock domains in an integrated circuit or circuit assembly in self-test or scan-test mode, where N>1 and each domain has a plurality of scan cells. The method and apparatus allows generating and loading N pseudorandom or predetermined stimuli to all the scan cells within the N clock domains in the integrated circuit or circuit assembly during the shift operation, applying an ordered sequence of capture clocks to all the scan cells within the N clock domains during the capture operation, compacting or comparing N output responses of all the scan cells for analysis during the compact/compare operation, and repeating the above process until a predetermined limiting criteria is reached. A computer-aided design (CAD) system is further developed to realize the method and synthesize the apparatus.
19 Citations
21 Claims
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1. An apparatus for providing ordered capture clocks to detect or locate faults within N clock domains and faults crossing any two clock domains in an integrated circuit or circuit assembly in scan-test or self-test mode, where N>
- 1, each clock domain having one capture clock and a plurality of scan cells, each capture clock comprising a plurality of capture clock pulses;
said apparatus comprising;(a) means for generating and shifting-in N test stimuli to all said scan cells within said N clock domains in said integrated circuit or circuit assembly during a shift-in operation; (b) means for applying an ordered sequence of capture clocks to all said scan cells within said N clock domains, the ordered sequence of capture clocks comprising at least a plurality of capture clock pulses from two or more selected capture clocks placed in a sequential order such that all clock domains are never triggered simultaneously during a capture operation; and (c) means for analyzing output responses of all said scan cells to locate any faults therein. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
- 1, each clock domain having one capture clock and a plurality of scan cells, each capture clock comprising a plurality of capture clock pulses;
Specification