In-Circuit Test Vector Synthesis for High Density Assembly Modifications
Vector synthesis for modified assemblies requires delta netlist verification, BSDL timing re-validation, and algorithmic backdrive current bounds.
Fault Dictionary
Meaning
A structured database that maps specific failure behaviors to their corresponding physical defect locations provides the foundation for rapid board diagnostics. Within a fault dictionary, every possible circuit fault is simulated to record its unique output signature under a given set of test patterns. This reference allows software to match actual test failures with simulated scenarios.
Database Generation
Electronic design automation software generates the lookup table during the post-synthesis simulation phase. The tool injects simulated faults, such as stuck-at-one or stuck-at-zero conditions, and records the resulting test vector outputs. This simulation process requires substantial computing power but saves time during production.
Diagnostic Lookup
When a circuit board fails a test, the automated test equipment extracts the failure signature and queries the database. The software searches for matching entries to find the list of candidate faults. This lookup process takes seconds and delivers a prioritized list of likely failure locations.
Silicon Application
Modern systems must handle complex behavior that goes beyond simple static models. Dynamic faults and bridging faults between adjacent traces generate complex signatures that require multi-valued dictionaries. The lookup system must adapt to these complex behaviors by calculating similarity scores rather than expecting exact matches.
This probabilistic approach ensures robust diagnostics even in the presence of noise or multiple simultaneous failures. By maintaining these records, manufacturers can track recurring defects and adjust the fabrication process to improve overall yield.