Bulk switching instrumentation amplifier for a high-impedance source in neural signal recording

Myungjin Han, Boram Kim, Yi An Chen, Hyojung Lee, Seung Han Park, Eunji Cheong, Jongill Hong, Gunhee Han, Youngcheol Chae

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


Flicker noise is the most crucial issue in an instrumentation amplifier (IA) for neural recordings because low-frequency neural signals overlap with the frequency of the amplifier's flicker noise. A Chopping technique, often used to reduce the flicker noise, is not desirable for high-impedance input sources due to the charge injection and clock feedthrough from the MOSFETs of the input chopper to the signal source, resulting in a significant increase in the total input-referred noise. Whereas MOSFETs have less flicker noise at the moment of turning on, and the intrinsic flicker noise can be then reduced by turning on and off the MOSFETs in the IA. This brief proposes a bulk switching IA, which can avoid the input current noise. A prototype IA is implemented in a 65 nm CMOS occupying 0.053 mm2, and it achieves the input-referred noise of 0.74 μVrms (local field potential) for 100 k Ω source impedance, a 3.3 times reduction compared with that of the chopper IAs, while consuming only 3.96 μW from a 1.2 V supply.

Original languageEnglish
Article number6949641
Pages (from-to)194-198
Number of pages5
JournalIEEE Transactions on Circuits and Systems II: Express Briefs
Issue number2
Publication statusPublished - 2015 Feb

Bibliographical note

Publisher Copyright:
© 2014 IEEE.

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


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