题目/Title：A 120dB SNDR Audio Sigma-Delta Modulator with an Asynchronous SAR Quantizer

作者/Author：叶亚飞,刘力源,李江源,李冬梅,王志华
                        Yafei Ye,Liyuan Liu,Jiangyuan Li,Dongmei Li,Zhihua Wang

会议/Conference：ISCAS 2012

地点/Location：Seoul, Korea

年份/Issue Date：2012.20-23 May

页码/pages：pp. 2357 - 2360

摘要/Abstract：
This paper presents a single loop 3rd order 5-bit audio  modulator with feed forward path. Feed forward technology relaxes the amplifier design requirement by reducing output swing of the integrators. Chopper stabilization technology is employed to mitigate the flicker noise introduced by 1st 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 2.3x1 mm2 fabricated in 0.18m standard CMOS.