A single die 124dB stereo audio delta sigma ADC with 111dB THD

A high performance, low power consumption, single die stereo delta sigma ADC is designed for professional audio and high precision measurement applications. A single loop, fifth-order, thirty-three level delta-sigma analog modulator with positive and negative feedforward path is implemented. An interpolated multilevel quantizer with unevenly weighted quantization levels replaces a conventional 5-bit flash type quantizer in this design. These new techniques suppress signal dependent energy inside the delta sigma loop, reduce internal channel coupling and power consumption. Integrated with an on-chip bandgap reference circuit and decimation filter, the ADC achieves 124 dB dynamic range (A-weighted), -111 dB THD over 20 kHz bandwidth. Inter-channel isolation is 130 dB. Total power consumption is less than 330 mW.