DAC waveform effects in CT incremental ΣΔ ADCs for biosensor applications

Incremental sigma-delta (IΣΔ) analog-to-digital converters (ADCs), which are essentially ΣΔ ADCs with periodic resetting, are well suited for low-power low-speed biosensor applications. In recent years, the potential advantage in terms of power dissipation of continuous-time (CT) IΣΔ ADCs have been explored. This paper analyzes the impact of feedback digital-to-analog converters (DACs) on the performance of CT IΣΔ ADCs. Different feedback DAC schemes are firstly analyzed and then evaluated by employing them in a 3^rd order single-bit CT IΣΔ ADC. Simulation results are discussed considering the trade-off between the timing error sensitivity and the power consumption, thereby offering a reference for selecting a power efficient feedback DAC scheme.