A Low Power Audio Delta-Sigma Modulator with Opamp-Shared and Opamp-Switched Techniques

A high power efficient opamp-shared and opamp-switched delta-sigma modulator (DSM) has been presented. It employs a fourth-order single loop 17-level DSM with an input feed forward gain stage. It is shown that power consumption can be largely reduced by using half delay integrators and switched opamp, and sharing opamp between integrator stages. The proposed DSM, designed on 0.35μm TSMC process under 1.8V supply, achieves 121μW power dissipation with 20 kHz bandwidth and 111.9dB Signal-to-Quantization Noise Ratio (SQNR).