A 50V Chopper Operational Amplifier With 1.3V/×s Common-Mode Transients Tolerance

This paper describes a high voltage (HV), slew-rate enhanced chopper-stabilized capacitively-coupled op-amp (CCOPA) for industrial applications. The op-amp utilizes a HVcompatible common-mode feedforward (CMFF) circuit to tolerate significant and rapidly changing CM transients up to $1.3 \mathrm{~V} / \mu \mathrm{s}$. A ping-pong coupling capacitor biasing technique is used to reduce the accumulated ripple associated with closed-loop CC-OPA. Fabricated on a standard $0.18 \mu \mathrm{~m}$ BCD process, this work achieves $14 \mathrm{nV} / \sqrt{ } \mathrm{Hz}$ input-referred noise, 140 dB CMRR, and $7.6 \mathrm{~V} / \mu \mathrm{s}$ slewrate while consuming 1.15 mA from a 5 V to 50 V supply voltage.