31.4 A Chopper-Stabilized Amplifier with -107dB IMD and 28dB Suppression of Chopper-Induced IMD

Thije Rooijers; Shoubhik Karmakar; Yoshinori Kusuda; Johan H. Huijsing; Kofi A.A. Makinwa

doi:10.1109/ISSCC42613.2021.9365790

31.4 A Chopper-Stabilized Amplifier with -107dB IMD and 28dB Suppression of Chopper-Induced IMD

Thije Rooijers, Shoubhik Karmakar, Yoshinori Kusuda, Johan H. Huijsing, Kofi A.A. Makinwa

Research output: Chapter in Book/Conference proceedings/Edited volume › Conference contribution › Scientific › peer-review

3 Citations (Scopus)

217 Downloads (Pure)

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.

Original language	English
Title of host publication	2021 IEEE International Solid-State Circuits Conference, ISSCC 2021 - Digest of Technical Papers
Publisher	IEEE
Pages	438-440
Number of pages	3
ISBN (Electronic)	9781728195490
DOIs	https://doi.org/10.1109/ISSCC42613.2021.9365790
Publication status	Published - 2021
Event	2021 IEEE International Solid-State Circuits Conference, ISSCC 2021 - San Francisco, United States Duration: 13 Feb 2021 → 22 Feb 2021

Publication series

Name	Digest of Technical Papers - IEEE International Solid-State Circuits Conference
Volume	64
ISSN (Print)	0193-6530

Conference

Conference	2021 IEEE International Solid-State Circuits Conference, ISSCC 2021
Country/Territory	United States
City	San Francisco
Period	13/02/21 → 22/02/21

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.

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Cite this

Rooijers, T., Karmakar, S., Kusuda, Y., Huijsing, J. H., & Makinwa, K. A. A. (2021). 31.4 A Chopper-Stabilized Amplifier with -107dB IMD and 28dB Suppression of Chopper-Induced IMD. In 2021 IEEE International Solid-State Circuits Conference, ISSCC 2021 - Digest of Technical Papers (pp. 438-440). Article 9365790 (Digest of Technical Papers - IEEE International Solid-State Circuits Conference; Vol. 64). IEEE. https://doi.org/10.1109/ISSCC42613.2021.9365790

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title = "31.4 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.",

author = "Thije Rooijers and Shoubhik Karmakar and Yoshinori Kusuda and Huijsing, {Johan H.} and Makinwa, {Kofi A.A.}",

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. ; 2021 IEEE International Solid-State Circuits Conference, ISSCC 2021 ; Conference date: 13-02-2021 Through 22-02-2021",

year = "2021",

doi = "10.1109/ISSCC42613.2021.9365790",

language = "English",

series = "Digest of Technical Papers - IEEE International Solid-State Circuits Conference",

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Rooijers, T, Karmakar, S, Kusuda, Y, Huijsing, JH & Makinwa, KAA 2021, 31.4 A Chopper-Stabilized Amplifier with -107dB IMD and 28dB Suppression of Chopper-Induced IMD. in 2021 IEEE International Solid-State Circuits Conference, ISSCC 2021 - Digest of Technical Papers., 9365790, Digest of Technical Papers - IEEE International Solid-State Circuits Conference, vol. 64, IEEE, pp. 438-440, 2021 IEEE International Solid-State Circuits Conference, ISSCC 2021, San Francisco, United States, 13/02/21. https://doi.org/10.1109/ISSCC42613.2021.9365790

31.4 A Chopper-Stabilized Amplifier with -107dB IMD and 28dB Suppression of Chopper-Induced IMD. / Rooijers, Thije; Karmakar, Shoubhik; Kusuda, Yoshinori et al.
2021 IEEE International Solid-State Circuits Conference, ISSCC 2021 - Digest of Technical Papers. IEEE, 2021. p. 438-440 9365790 (Digest of Technical Papers - IEEE International Solid-State Circuits Conference; Vol. 64).

Research output: Chapter in Book/Conference proceedings/Edited volume › Conference contribution › Scientific › peer-review

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AU - Rooijers, Thije

AU - Karmakar, Shoubhik

AU - Kusuda, Yoshinori

AU - Huijsing, Johan H.

AU - Makinwa, Kofi A.A.

N1 - 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.

PY - 2021

Y1 - 2021

N2 - 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.

AB - 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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Rooijers T, Karmakar S, Kusuda Y, Huijsing JH , Makinwa KAA. 31.4 A Chopper-Stabilized Amplifier with -107dB IMD and 28dB Suppression of Chopper-Induced IMD. In 2021 IEEE International Solid-State Circuits Conference, ISSCC 2021 - Digest of Technical Papers. IEEE. 2021. p. 438-440. 9365790. (Digest of Technical Papers - IEEE International Solid-State Circuits Conference). doi: 10.1109/ISSCC42613.2021.9365790

31.4 A Chopper-Stabilized Amplifier with -107dB IMD and 28dB Suppression of Chopper-Induced IMD

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