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Abstract Test sets that target standard fault models may not always be sufficient for detecting all defects. To evaluate test sets for the detection of unmodeled defects,n-detect test sets (which detect all modeled faults at leastntimes) have previously been proposed. Unfortunately,n-detect test sets are often prohibitively long. In this paper, we investigate the ability of shadow flip-flops connected into a MISR (Multiple Input Signature Register) to detect stuck-at faults fortuitously multiple times during scan shift. We explore which flip-flops should be shadowed to increase the value ofnfor the least detected stuck-at faults for each circuit studied. We then identify which circuit characteristics are most important for determining the cost of the MISR needed to achieve high values ofn. For example, circuits that contain a few flip-flops with upstream fault cones that cover a large percentage of all faults in the circuit can often achieve highn-detect coverage fortuitously with a low-cost MISR. This allows a DFT engineer to predict the viability of this MISR-based approach early in the design cycle.
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Dual Use Circuitry for Early Failure Warning and Test
Incorrect circuit timing often leads to errors in the field, including silent data corruption. Once a circuit violates timing, recovery can be difficult even when the violation is detected. Canary flip-flops have previously been proposed to identify when the desired slack of a path has first been violated in functional mode even before failure occurs. We show how such flip-flops can be combined in a MISR to also provide enhanced coverage during manufacturing test and scan-based field test.
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- Award ID(s):
- 1812777
- PAR ID:
- 10509333
- Publisher / Repository:
- IEEE
- Date Published:
- ISBN:
- 979-8-3503-0927-0
- Page Range / eLocation ID:
- 1 to 8
- Subject(s) / Keyword(s):
- Canary Flip-flops, Design for Test, Fault Coverage, Silent Data Corruption (SDC)
- Format(s):
- Medium: X
- Location:
- San Francisco, CA, USA
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/ISQED60706.2024.10528709
