Design for Test and Fault Simulation of Electronic Circuits
: The increasing complexity of circuits and decreasing components size has made the testability and simulation of electronic circuits to be considered crucial and demanding. Therefore, there is need to employ Design for Test (DFT) and fault simulation concepts from the earliest stages of the product design because it impacts all areas of the design of a product from the initial concept to the component choice, investment in test equipments and mechanical design in order to eliminate faults and fabrication defects in the electronic circuits. Furthermore, there is need to design in some circuitry which allows the equipment to test itself (Built-In Self-Test) or allows it to be tested by an external tester (Automatic Testing Equipment). The circuit is simulated to make sure the added test circuitry (BIST or ATE) has not affected the operation of the new circuit. A set of test vectors for the circuit will be written afterwards by the designer if the new circuit passes simulation. A program called a fault simulator is then used to determine the percentage of internal faults that can be detected in the circuit when specified set of test vectors is applied to it. If the test vectors cannot detect an acceptable percentage of faults in the circuits then more test vectors must be written or the circuit must be re-designed so that faults are more detectable.