On-chip Digital Calibration of Low-voltage Operational Amplifier in CMOS

This paper proposes an analysis of digital method of input offset compensation in operational amplifier, integrated as a single system in 130 nm CMOS technology. The whole system operates with 0.6 V supply voltage and consumes less than 80 µW of power. The paper includes small-signal analysis investigating possible adverse effects of added calibration hardware on the calibrated amplifier. Proposed solution was verified through Monte Carlo simulations in temperature range from −20°C to85°C in Cadence design environment. Using the proposed method of calibration, the input offset voltage of operational amplifier was suppressed from 278 µV to 22 µV (in terms of mean value).