A Fill-In Technique for Robust IMD Suppression in Chopper Amplifiers

A Fill-In Technique for Robust IMD Suppression in Chopper Amplifiers

Rooijers, C.T. (TU Delft Electronic Instrumentation)
Karmakar, S. (TU Delft Electronic Instrumentation)
Kusuda, Y. (Analog Devices)
Huijsing, J.H. (TU Delft Electronic Instrumentation)
Makinwa, K.A.A. (TU Delft Microelectronics)

Microelectronics

2021

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_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.

Auto-zeroing
chopping
dynamic offset compensation
fill-in technique
Intermodulation distortion

http://resolver.tudelft.nl/uuid:2f23b74b-2675-490a-b6fd-69479c7808d2

https://doi.org/10.1109/JSSC.2021.3107350

2022-04-11

1558-173X

IEEE Journal of Solid State Circuits, 56 (12), 3583-3592

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.

Institutional Repository

journal article

© 2021 C.T. Rooijers, S. Karmakar, Y. Kusuda, J.H. Huijsing, K.A.A. Makinwa