Robust analogue background calibration technique for multi-bit switched capacitor DACs

A robust analogue calibration technique to continuously correct for element mismatch in multi-bit switched capacitor DACs is proposed. Unlike most existing analogue calibration techniques, its accuracy is not limited by the mismatch of charge injection that is outside of the calibration loop. Using the proposed technique, multi-bit switched-capacitor DACs the linearity of which is only limited by the calibration loop gain can be realised. Simulation results show that the INL of a switched-capacitor DAC improves from 8-bit level to 15-bit level with the proposed calibration.