A 40kHz-BW 90dB-SNDR Noise-Shaping SAR with 4× Passive Gain and 2nd-Order Mismatch Error Shaping

📋 论文概要

该论文提出了一种具有4倍无源增益和二阶失配误差整形的噪声整形逐次逼近寄存器（SAR）模数转换器（ADC），解决了无源环路滤波器无法提供增益导致的噪声抑制有限问题，实现了40kHz带宽、90dB SNDR的高分辨率。

💡 主要创新点

• 通过无源增益技术实现4倍电压增益，有效抑制比较器噪声和kT/C噪声。
• 采用二阶失配误差整形技术，降低电容失配影响，提升线性度。
• 结合无源电压求和，避免多路径比较器，进一步降低噪声和功耗。

🏷 关键词

📄 原文摘要

have drawn increasing attention due to their simplicity, low power, zero static current, and PVT robustness. However, prior works show limited resolution (ENOB(13b) due to two main challenges. The 1st one is thermal noise. Passive loop filters cannot provide gain [1]. Hence, their suppression of the comparator noise is limited. In addition, every capacitor switching introduces extra kT/C noise. To reduce noise, a passive gain of 2 is realized in [2]. It also realizes passive voltage summation, which obviates the need for a multipath comparator, further reducing the comparator noise. Nevertheless, it uses small capacitors for residue sampling to minimize signal attenuation, leading to a large total kT/C noise of 20kT/C (C is the DAC size). Also, its NTF is mild (zero at 0.5), leading to limited SQNR benefit. The

👥 作者与机构

Jiaxin Liu1, Xing Wang1, Zijie Gao1, Mingtao Zhan1, Xiyuan Tang2, Nan Sun2

Tsinghua University, Beijing, China University of Texas, Austin, TX 1 2 Noise-shaping (NS) SAR ADCs using passive loop filters