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.
Diagnostic Resolution
Meaning
The precision with which a test system can isolate a detected failure to a specific component or node defines the effectiveness of a diagnostic routine. Achieving high diagnostic resolution ensures that repair technicians can quickly replace the failed part without causing collateral damage. It acts as a primary metric for evaluating the performance of both in-circuit and functional test programs.
Ambiguity Reduction
Reducing the size of the suspect list is the main goal of diagnostic optimization. When a test fails, the system ideally points to a single component, representing perfect resolution. Frequently, however, the failure signature is shared by multiple devices on the same net, resulting in an ambiguity group.
Software Dictionary
Automated test programs compile database records that correlate known failure patterns with their root causes. The software compares the active fault signature against this dataset to pinpoint the most likely source of the issue. This comparison allows the system to prioritize repair actions based on statistical probability.
Hardware Optimization
Adding physical test points or boundary scan nodes directly increases the system’s ability to divide and conquer circuit blocks. Without these measurement nodes, the diagnostic software must rely on complex functional behavior, which broadens the ambiguity group. Designers must negotiate the trade-off between the physical space required for extra test points and the long-term repair costs associated with low resolution.
High resolution lowers the total cost of ownership by reducing diagnostic and rework time on the production floor.