Fault Detection and Parameter Prediction of an OpAmp using a Charge Monitor

In this paper we present a new tool to improve analog circuits test. This tool is based on measuring not only frequency or voltage, but also the transferred charge during a period while the circuit under test is configured as an oscillator. To prove the technique, fault diagnosis and parameter prediction have been tried. Simulations have been performed on an opamp considering process variations in both fault-free and defective circuits. These simulations show that both fault coverage and yield of the test process obtained using frequency or voltage amplitude can be greatly improved by adding charge as a test observable. Moreover, parameter prediction is also improved