Predictive Oscillation Based Test of CMOS circuits

Two different CMOS circuits has been used to check the predictive oscillation based test (POBT) approach, combined with supply current monitoring technique. These circuits are a two stage op amp and a biquad filter composed by two transconductance amplifiers (OTA). The combination of both techniques has given excellent results in predicting the main performance parameters of the circuits as DC gain, bandwidth or slew-rate in the opamp and cut-off frequency, quality factor or rise time in the filter. When considering tolerances in the fabrication process, correlation coefficients higher than 0.998 for the opamp and 0.95 for the biquad filter have been found. These good results open the door to a new built in test strategy, and alleviates the need of more complex techniques to enhance the efficiency of the POBT requiring sophisticated acquisition systems