Title
31.4 A Chopper-Stabilized Amplifier with -107dB IMD and 28dB Suppression of Chopper-Induced IMD
Author
Rooijers, C.T. (TU Delft Electronic Instrumentation) 
Karmakar, S. (TU Delft Electronic Instrumentation)
Kusuda, Yoshinori (Analog Devices)
Huijsing, J.H. (TU Delft Electronic Instrumentation)
Makinwa, K.A.A. (TU Delft Microelectronics)
Department
Microelectronics
Date
2021
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.
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http://resolver.tudelft.nl/uuid:d1271354-0c61-4ba9-a067-8af64c2c2724
DOI
https://doi.org/10.1109/ISSCC42613.2021.9365790
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Embargo date
2021-09-03
ISBN
9781728195490
Source
2021 IEEE International Solid-State Circuits Conference, ISSCC 2021 - Digest of Technical Papers
Event
2021 IEEE International Solid-State Circuits Conference, ISSCC 2021, 2021-02-13 → 2021-02-22, San Francisco, United States
Series
Digest of Technical Papers - IEEE International Solid-State Circuits Conference, 0193-6530, 64
Bibliographical note
Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Part of collection
Institutional Repository
Document type
conference paper
Rights
© 2021 C.T. Rooijers, S. Karmakar, Yoshinori Kusuda, J.H. Huijsing, K.A.A. Makinwa