DAC compensation for continuous-time delta-sigma modulators

This paper presents a novel compensation technique that compensates for the intersymbol interference and excess loop delay in the 1-bit feedback DAC of a continuous-time (CT) delta-sigma modulator (ΔΣM). The technique does not require a prior knowledge of the NRZ DAC output pulse in response to the input transition. As such, it could potentially compensate for most of the NRZ DAC nonidealities at high sampling frequency. A fourth-order bandpass continuous-time delta-sigma modulator is simulated to verify the effectiveness of the proposed DAC compensation technique.