Stuck-at-Fault Model (SAF) A stuck-at-fault (SAF) model represents a fault in a circuit where a single element, like a transistor or a memory cell, is perman...
A stuck-at-fault (SAF) model represents a fault in a circuit where a single element, like a transistor or a memory cell, is permanently stuck in a specific state. This can lead to catastrophic failures in the entire system, as any input that reaches the faulty element will be ignored and cannot trigger the desired output.
Example: A stuck-at-fault transistor in a digital circuit can cause an output logic level to remain stuck at 0 or 1, leading to incorrect readings or malfunctions.
Bridging faults are a technique used to test the functionality of a circuit by intentionally introducing faults at various locations. By analyzing the behavior of the system when these faults are present, engineers can identify and isolate the source of the problem.
Example: In a circuit containing a memory cell and a switch, a bridge fault could be introduced by connecting the switch's control pin directly to the memory cell's data input. This will force the memory cell to output its current state regardless of the switch's position, allowing engineers to determine if the memory cell is faulty.
Transition faults are a type of fault where the behavior of the system changes abruptly at a specific input value. This type of fault can be used to test the robustness and fault tolerance of a circuit.
Example: A transition fault in a digital circuit could be induced by introducing a high-level input that exceeds the circuit's threshold voltage. This will cause the circuit to transition from a normal to a faulty state, revealing potential faults in the input or output circuits