Efficient Calibration of Feedback DAC in Delta Sigma Modulators

Feedback digital to analog converter non-linearity is one of the factors that limit performance of delta sigma modulators. Various mismatch shaping and non-linearity calibration schemes exist, but they either require additional element shuffling hardware or reconfiguration of the sigma delta modulator for calibration. In this brief, an efficient in-situ calibration scheme is presented which neither requires any analog hardware nor requires reconfiguration for calibration. Simulation results show that calibrated coefficients can be used to correct for mismatch induced increase in noise floor and non-linearity to achieve nearly ideal performance.