A 0.9-V 60-mu W 1-bit fourth-order delta-sigma modulator with 83-dB dynamic range

Abstract

A 0.9-V 60-mu W delta-sigma modulator is designed using standard CMOS 0.13-mu m technology. The modulator achieves 83-dB dynamic range in a signal bandwidth of 20 kHz with a sampling frequency of 2 MHz. The input-feedforward architecture is used to reduce the voltage swing of the integrators, which enables low-power amplifiers. By considering the characteristics of the modulator architecture, low-quiescent operational transconductance amplifiers are designed, which use positive feedback to increase dc gain. The designed modulator shows very high figure of merit among the state-of-the-art sub-I-V modulators.