A 79dB-SNDR 167dB-FoM Bandpass ΔΣ ADC Combining N-Path Filter with Noise-Shaping SAR Figure 27.7.3 shows the NS-SAR schematic and timing diagram. The LPF tracking and the SAR conversion take up 1/8 and 3/8 of a clock period, respectively. The rest is allocated for the residue amplification and integration.

📋 论文概要

该论文提出了一种结合N-path滤波与噪声整形SAR的带通ΔΣ ADC，实现了79dB SNDR和167dB FoM。通过采用顶板采样、断开CDAC与非线性输入电容的开关以及浮动逆变放大器拓扑，解决了线性度、功耗和共模反馈问题。

💡 主要创新点

• 采用顶板采样并使用两个开关断开CDAC与比较器和动态放大器的非线性输入电容，提高了线性度。
• 采用浮动逆变放大器（FIA）动态放大器拓扑，实现2倍电流复用，无需共模反馈电路，保持恒定性能。

🏷 关键词

📄 原文摘要

For simplicity of design, this work uses top-plate sampling. To improve its linearity, 2 switches are used to disconnect CDAC from the nonlinear input capacitance of the comparator and the dynamic amplifier (DA) during the input tracking phase [5]. After tracking, the ADC performs 10b SAR conversion. Then, the residue is amplified by the DA. This work adopts the floating inverter amplifier (FIA) DA topology [6]. It achieves 2× current reuse and provides a high gain. Moreover, because the DA is powered by a floating reservoir capacitor, CB, it does not need any CMFB circuit and maintains a constant output common-mode voltage against variations in the input common-mode voltage and PVT. In the proposed BPDSM, there are 2 merits to use residue preamplification before integration: 1) it prevents signal charge loss on the sampling capacitor and maintains the correct N-path filter operation; 2) it suppresses the noise

👥 作者与机构

Linxiao Shen1,2, Zijie Gao3, Xiangxing Yang2, Wei Shi2, Nan Sun2,3