A Low-Distortion Low-Power MASH Architecture ΣΔ Modulator with Double-Sampling

Abstract

This paper presents a low-distortion and low-power multi-stage noise-shaping (MASH) architecture Sigma-Delta ([Formula: see text] modulator with double-sampling. The modulator uses a cascade of integrator feed-forward (CIFF) structure as a cascaded modulator in a MASH architecture. Since the CIFF structure provides a feedforward path from the input signal to the quantizer, the input signal is directly transmitted to the output without loop processing, relaxing the linearity requirement of the modulator, reducing performance requirements for the OTA and harmonic distortion. Double-sampling technique is adopted in the first integrator to double the sampling rate, improving the accuracy of the modulator without the increase of power consumption. In order to eliminate the influence of capacitor mismatch in the sampling network, a fully floating differential switched capacitor (SC) feedback digital-to-analog (DAC) is used in the integrator. The simulation results show that the [Formula: see text] modulator achieves 113[Formula: see text]dB signal-to-noise and distortion ratio (SNDR) and the power consumption is 3.15[Formula: see text]mW from a 5[Formula: see text]V power supply.