Paper Info
Title
A Chopper-Stabilized Amplifier With-107db Imd And 28db Suppression Of Chopper-Induced Imd
Abstract
Amplifiers often employ chopping to achieve low offset and low-frequency noise. However, the interaction between the input signal and the chopper clock can cause chopper-induced intermodulation distortion (IMD) [1] –[5]. This is especially problematic for input frequencies (Fin) near even multiples of the chopping frequency (FCH), as the resulting IMD tones fold-back to low frequencies and so cannot be filtered out. In [2] –[4], spread-spectrum clocks are used to convert such tones into noise-like signals. However, this increases the noise floor and does not address the underlying problem. This paper shows that chopper-induced IMD is mainly due to amplifier delay, which results in large chopping spikes. A novel fill-in technique is proposed that mitigates these spikes, and so reduces the chopper-induced IMD. In a prototype chopper-stabilized amplifier, it reduces the chopper-induced IMD by 28dB, resulting in an IMD of -126dB for input frequencies near 4FCH (=80kHz). Similarly, it improves the chopped amplifier’s two-tone IMD (79 and 80kHz) from -97dB to -107dB, thus maintaining the same IMD as the un-chopped amplifier.
Year
DOI
Venue
2021
10.1109/ISSCC42613.2021.9365790
2021 IEEE INTERNATIONAL SOLID-STATE CIRCUITS CONFERENCE (ISSCC)
DocType
Volume
ISSN
Conference
64
0193-6530
Citations 
PageRank 
References 
0
0.34
0
Authors
5
Name
Order
Citations
PageRank
Thije Rooijers131.78
Shoubhik Karmakar2113.84
Yoshinori Kusuda3124.70
Johan H. Huijsing492.98
Kofi A. A. Makinwa5506105.58