What Are Bridging Faults?
When a short develops between two unconnected signal lines of a logic gate, bridging faults occur. A bridging failure in a combinational circuit can generate logical oscillations, even if an inter-gate short between disconnected lines does not appear to be dangerous. Feedback bridging faults can turn a combinational circuit with an output that is solely determined by the state of its inputs into a sequential circuit with an output that is determined by the inputs' timing. To make matters worse, bridging faults might occur in a single or numerous circuits. A multiple bridging fault might imitate several single bridging faults that have common lines, as opposed to a single bridging fault that only impacts two lines.
Different Types Of Bridging Faults
Different kinds of bridging faults can occur in a circuit like wired-AND, wired-OR, A dominating B or vice-versa. For simple understanding, we can model these bridging faults in a gate level presentation.
Truth Table:
From the table we can find out what kind of bridging fault has occurred between input As and Bs. The corresponding golden response or expected output is Ad and Bd. For example, in a A dominant-AND B bridging fault if we give AsBs = 01 the expected output from AdBd is 01 but we get 00. So we can say, the input As has dominated the input Bs and the dominance between them can be modeled as an AND gate in this case.
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