An 84dB-SNDR Low-OSR 4th-Order Noise-Shaping SAR with an FIA-Assisted EF-CRFF Structure and Noise-Mitigated Push-Pull Buffer-in-Loop Technique

📋 论文概要

该论文提出了一种低过采样率（OSR<8）的四阶噪声整形逐次逼近寄存器（NS-SAR）模数转换器，通过浮空反相放大器（FIA）辅助的EF-CRFF结构实现高阶噪声整形，并采用噪声抑制的推挽缓冲器来提升功耗效率，最终实现了84dB SNDR的高分辨率。

💡 主要创新点

• 提出FIA辅助的EF-CRFF结构，在低功耗硬件下实现了四阶优化噪声整形，克服了低OSR下高阶NS的稳定性与功耗折衷。
• 采用噪声抑制的推挽缓冲器，降低了缓冲器引入的噪声，进一步提升了整体信噪比和能效。
• 通过系统级架构优化，在低OSR条件下同时实现了高SNDR和低功耗，拓展了NS-SAR在宽带应用中的适用性。

🏷 关键词

📄 原文摘要

*Equally Credited Authors (ECAs) With the combined merits of SAR and ∆Σ ADCs, the noise-shaping (NS) SAR architecture can achieve high resolution with a mild OSR, making it versatile for a wide range of applications. Nonetheless, designing a highly power-efficient NS-SAR under relatively low OSRs (<8) can be challenging. It requires the design to concurrently address two key considerations. The first is to implement high-order optimized NS with simple and low-power hardware that maximally preserves the efficient nature of the SAR. In this regard, two recent works report 4th-order NS using a cascaded EF structure [1] and an FVF-assisted CIFF structure [2] respectively, both allowing aggressive NTFs to be realized with simple open-loop amps. However, they still employ static amps/buffers, which limit the power improvement. Also, the lack of NTF optimization makes them non-ideal for low OSR designs. The second concern is the growing kT/C noise contribution under low

👥 作者与机构

Tzuhan Wang*, Tian Xie*, Zhe Liu, Shaolan Li

Georgia Institute of Technology, Atlanta, GA