A Stereo Audio Delta-Sigma DAC with 40-kHz Bandwidth and 103-dB SNR

A wide-band and low-noise stereo delta-sigma (Delta Sigma) digital-to-analog converter (DAC) for audio applications is proposed. A multi-bit quantizer with data-weighted averaging is used to reduce quantization noise and a half-band finite impulse response filter is designed to increase the speed of the Delta Sigma modulator. A direct-charge-transfer switched-capacitor DAC and a track-and-hold circuit with a deglitch timing are used to improve the operating speed and the linearity of the audio DAC. The chip is fabricated with a 0.13-mu m CMOS process, which uses the supply voltages of 1.2 V for the digital domain and 3.3 V for the analog domain. The experimental results show that our audio DAC achieves 40-kHz bandwidth, 103-dB A-weighted signal-to-noise ratio, and -85-dB total harmonic distortion and noise.