一种实现失配误差整形与4倍无源增益的噪声整形SAR ADC

A Noise-Shaping SAR ADC with Mismatch Error Shaping and a Passive Gain of 4

本文提出了一种高分辨率的完全无源的噪声整形逐次逼近型模数转换器(SAR ADC)。首先,其采用了一种二阶误差反馈式失配误差整形技术(EFMES),并且使用了一种数字预测方法来恢复MES引起的信号范围损失。其次,采用了一种完全无源的噪声整形结构,实现了无源求和与4倍无源增益,对系统内热噪声与量化噪声进行整形。最后。采用了一种差分式的定制电容,大大降低了电容阵列整体面积的同时依然保有良好的线性度。该设计使用SMIC 0.18μm工艺实现,后仿真表明,在1.8V电源电压、25倍过采样率和1MS/s的采样频率下,ADC的SNDR为88.23dB,SFDR为93.67dB。功耗仅为965μW,电路有效面积为1.95mm^(2)。

This paper presents a high-resolution fully passive NS SAR ADC.First,it uses a second-order mismatch error-feedback error shaping(EFMES),and uses a digital prediction method to recover the signal-range loss caused by the MES.Second,It uses an fully passive noise-shaping architecture that realizes the passive summation and the passive gain of 4,shape the thermal noise and the Quantization Noise inside the system.At last,it uses a differential custom capacitors,The overall area of the capacitor array is reduced while maintaining good linearity.This design uses the SMIC 0.18 process,Post-simulation shows that at the 1.8V power supply voltage and 1MS/s sampling rate,the SNDR of ADC is 88.23dB,the SFDR is 93.67dB.The total power consumption is only 965μW,and occupies an active area of 1.95mm^(2).