Mixed-Signal Circuit Classification in a Pseudorandom Testing Scheme

Pseudorandom testing techniques for mixed-signal circuits offer several advantages compared to explicit time-domain and frequency-domain test methods. To fully exploit these advantages a suitable choice of the pseudorandom input parameters should be made and an investigation of the accuracy of the circuit response samples needed to reduce the risk of misclassification should be carried out. Here these issues have been addressed for a testing scheme based on the estimation of the impulse response of the device under test (DUT) by means of input-output cross-correlation. Moreover, new acceptance criteria for the DUT are suggested which solve some ambiguity problems arising if the classification of the DUT as good or bad is based on a few samples of the cross-correlation function. Examples of application of the proposed techniques to real cases are also shown in order to assess the impact of the measurement system inaccuracies on the reliability of the test.