A Fill-In Technique for Robust IMD Suppression in Chopper Amplifiers
A Fill-In Technique for Robust IMD Suppression in Chopper Amplifiers
复制标题
斩波放大器中稳健 IMD 抑制的填充技术
DOI：
10.1109/jssc.2021.3107350
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发表时间：
2021
影响因子：
5.4
通讯作者：
K. Makinwa
中科院分区：
文献类型：
--
作者：
Thije Rooijers;Shoubhik Karmakar;Y. Kusuda;J. Huijsing;K. Makinwa
在斩波放大器中，输入信号和斩波时钟之间的相互作用可能会引起互调失真（IMD）。斩波器引起的IMD主要是由于放大器延迟，这会在放大器的输出斩波器的输出端产生大脉冲。本文提出使用所谓的填充技术，通过多路复用正交斩波的两个相同放大器的输出来消除这些脉冲，从而消除由此产生的IMD。在180 nm CMOS工艺中实现了一个原型斩波稳定放大器。测量结果表明，填充技术抑制斩波引起的IMD 28 dB，导致在输入频率接近4 $F_{\mathrm {CH}}$（=80 kHz）的IMD为−126 dB。它还将放大器的双音IMD（79 kHz和80 kHz输入）从−97 dB提高到−107 dB，与不斩波时的结果相同。
In chopper amplifiers, the interaction between the input signal and the chopper clock can give rise to intermodulation distortion (IMD). This chopper-induced IMD is mainly due to amplifier delay, which causes large pulses at the output of the amplifier’s output chopper. This article proposes the use of a so-called fill-in technique to eliminate these pulses, and thus the resulting IMD, by multiplexing the outputs of two identical amplifiers that are chopped in quadrature. A prototype chopper-stabilized amplifier was implemented in a 180-nm CMOS process. Measurements show that the fill-in technique suppresses chopper-induced IMD by 28 dB, resulting in an IMD of −126 dB for input frequencies near 4 $F_{\mathrm {CH}}$ (=80 kHz). It also improves the amplifier’s two-tone IMD (with 79 and 80 kHz inputs) from −97 to −107 dB, which is the same as that obtained without chopping.