A 60-V Chopper Amplifier Achieving 0.12- μ V Ripple and 2- μ V V OS Over Full Temperature With Calibration

This brief presents a 60 V chopper-stabilized operational amplifier (opamp) with an 8 MHz gain-bandwidth product (GBW) and precision calibration. A novel high-voltage adaptive clock-bootstrap technique is proposed, compensates for temperature variations of the threshold voltage, and maintains a constant overdrive voltage. The opamp integrates a 500× gain module to amplify and calibrate the non-chopped offset voltage, thereby reducing output ripple. It adopts a calibration scheme with temperature-compensated bit weights which are proportional to the transconductance of the chopper-path input transistor pair. Fabricated in a 0.18-μm Bipolar-CMOS-DMOS process, the amplifier employs input-referred offset and ripple minimization techniques while ensuring consistent performance over a wide input common-mode voltage range and temperature span, achieving a 3-σ offset voltage of 2 μV across 100 samples (-40 °C to 125 °C), an offset drift of 7 nV/°C, and a maximum input-referred ripple of 0.12 μVRMS (Root Mean Square).