Estimation of the Influence of Test Stimulus Precision on Test Quality for Parametric Faults in Analog Integrated Circuits

With the upcoming trend towards built-in test structures and implicit testing, more and more issues of test design need to be resolved during circuit design. A basic requirement for manual as well as for automatic test generation is to assess how accurately a given test strategy will classify good and faulty circuits. Measurement error plays an important role here and must be taken into account to assess the precision of a test strategy. A second, often underestimated cause of error is the limited degree of accuracy of analog test stimulus generation. In this paper, we propose a new method to evaluate and identify influences of test quality degradation due to measurement error and test stimulus variation. We will show that for analog testing, the precision of test stimulus generation and the precision of measuring the circuit’s response are of similar importance.