A self-calibrated binary weighted DAC in 90nm CMOS technology

In this paper, an on-chip self-calibrated 8-bit R-2R digital-to-analog converter (DAC) based on digitally compensated input offset of the operational amplifier (OPAMP) is presented. To improve the overall DAC performance, a digital offset cancellation method was used to compensate deviations in the input offset voltage of the OPAMP caused by process variations. The whole DAC as well as offset compensation circuitry were designed in a standard 90nm CMOS process. The achieved results show that after the self-calibration process, the improvement of 48% in the value of DAC offset error can be obtained.