Offset measurement method for accurate characterization of BTI-induced degradation in opamps

Bias temperature instability (BTI) has become one of the major concerns in reliable circuit design in advanced CMOS nanometer technology. It can have a significant impact on the performance of analog building blocks. To understand the effect of BTI in analog circuits, an accurate measurement of circuit parameter degradation by BTI has become very necessary. This paper proposes a measurement scheme of the input offset degradation of an operational transconductance amplifier (OTA) due to the BTI effect. Conventional offset measurement techniques do not take into account the BTI recovery. Therefore, the proposed scheme is targeted to measure degradation during the stressing to avoid relaxation. The concept behind the scheme is to present the offset degradation as a function of the propagation delay degradation. Simulation results are shown for the measurement circuit.