A 1/f Noise Upconversion Reduction Technique Applied to Class-D and Class-F Oscillators

📋 论文概要

该论文提出了一种降低1/f噪声上变频的技术，应用于Class-D和Class-F振荡器，以改善近载波相位噪声性能。该技术避免了现有方案需要额外可调电感或恶化20dB/dec区域相位噪声的缺点。

💡 主要创新点

• 提出一种新的1/f噪声上变频降低技术，不需要额外电感且不恶化20dB/dec区域相位噪声。
• 该技术适用于Class-D和Class-F两种振荡器架构，具有通用性。
• 通过抑制尾电流和gm器件的闪烁噪声上变频，显著降低1/f³相位噪声拐角。

🏷 关键词

📄 原文摘要

The 1/f (flicker) noise upconversion degrades the close-in spectrum of CMOS RF oscillators. The resulting 1/f3 phase noise (PN) can be an issue in PLLs with a loop bandwidth of <1MHz, which practically implies all cellular phones. A previously published noise-filtering technique [1] and adding resistors in series with gm-device drains [2] have shown significant reduction of the 1/f3 oscillator PN corner. However, the former needs an additional tunable inductor and the latter degrades PN in the 20dB/dec region. The flicker noise can upconvert via two major phenomena. First, tail current flicker noise can modulate the oscillating waveform amplitude, which can convert to PN through a nonlinear C-V characteristic of varactors and active devices. The second mechanism is the Groszkowski effect [3]: The presence of harmonic components of the active gm device current can cause a frequency drift of the tank resonance (see Fig. 25.4.1-top). The fundamental drain current IH1

👥 作者与机构

Mina Shahmohammadi, Masoud Babaie, Robert Bogdan Staszewski

Delft University of Technology, Delft, The Netherlands