This paper describes an analog front-end(AFE) intended for portable audio application, which operates at 1 V and consumes only 410 W. The AFE consists of a 30 d B-gain programmable gain amplifier(PGA) and a2nd-order 3-bit sigma-delta modulator. The PGA with single input and on-chip common-mode bias voltage shows good noise-reduction performance. The modulator makes use of data weighted averaging to reduce the linearity requirements of the digital-to-analog converter in the feedback loop. The AFE is implemented in the SMIC 0.13 m1P8 M CMOS process. The measurement results show that in a 1 V power supply, at 200 m Vp-p, between 100 Hz and 20 k Hz, the maximal signal-to-noise ratio is 70 d B, and the total power is 410 W.
