Analogue filter circuits testing using voltage and current measurements

This paper presents a study of the importance of analogue circuits testing in general and the challenges faced in testing these modules in a mixed-signal environment. It highlights the difficulties that are involved in testing analogue and mixed-signal circuits and compares them with those of testing digital only circuits. Sources of failure in integrated circuits and their relation to fault models are outlined. The paper concentrates on testing active analogue filter circuits operating in mid-range frequencies. A variety of filter circuits with different configurations and varied degrees of complexity are studied. Both soft and catastrophic single fault conditions are introduced to the circuits at the transistor, operational amplifier and feedback network levels. The work presented in the paper compares the detection of the injected faults using both frequency response and transient response voltage and current measurements. The objective is to determine the measurement method and parameter that is best at detecting a particular fault or class of faults. Analysis of the simulation data indicates that the measurement methods and parameters are complementary in terms of fault coverage and fault detection confidence.