A BICS for CMOS opamps by monitoring the supply current peak

We present a Built-In-Current-Sensor (BICS) based on monitoring the supply current peak of CMOS opamps using the oscillation-test-strategy. The BICS takes a weighed sample of the current through each opamp current branch and monitors the peak value under oscillation. An envelope detector and additional digital circuitry is used to provide a pass/fail flag. Simulation results demonstrate a high defect coverage with a very small impact on the opamp nominal operation.