A 120dB SNDR audio sigma-delta modulator with an asynchronous SAR quantizer

摘要

integrator. A kind of asynchronous successive approximation (SAR) quantizer without extra fast clock replaces the traditional flash quantizer. Two voltage reference buffers are integrated on this chip as the input stages of Vrefp and VCMO to simplify off-chip circuits. Simulation results show that the modulator achieves 120dB SNDR under 5 kHz input signal within 20Hz∼24kHz bandwidth. The modulator alone consumes only 20mW and the overall power consumption is less than 60mW from 3.3V supply. The active core area is 2.3×1 mm