Current test methods in mixed signal circuits

The increase in importance of mixed mode ASICs has brought about a new interest in testing this kind of circuit. Nevertheless, these techniques have not yet reached the same level of development as that achieved in digital circuits. Recently a lot of work has been done applying current test methods to analogue and mixed circuits probing the capability that these techniques have to unify the test of the analogue and the digital parts of the mixed circuits. In this paper we review the most effective techniques proposed for test pattern generation and fault detection for power supply current testing in mixed circuits. The use of quiescent, transient and the spectral analysis of the power supply consumption current are analysed and compared. The consideration of catastrophic and parametric faults made it necessary to apply spectral analysis and multivariate statistics to the power supply current signal. Experimental results of these methods are given in some analogue-digital circuits, such as a digital-to-analogue converter circuits.