A 300-pW audio ΑΣ modulator with 100.5-dB DR using dynamic bias inverter

A micropower audio delta-sigma modulator is presented for mobile applications. The modulator employs dynamic bias inverter based integrators, which maximizes both g m /I D ratio and slew rate while compensating PVT variations. A prototype modulator implemented in a 0.18pm CMOS process features a single-bit third-order topology. The modulator achieves 97.7dB SNDR, 98.6dB SNR, 100.5dB DR, and 105.8dB SFDR in a 20kHz audio band, while consuming only 300pW from a 1.8V supply. This corresponds to a state-of-the-art FoM of 178.7dB.