A 0.9-V 60-μW 1-Bit Fourth-Order Delta-Sigma Modulator With 83-dB Dynamic Range

A 0.9-V 60-muW delta-sigma modulator is designed using standard CMOS 0.13-mum 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-l-V modulators.