A Nanopower EEG Low-Pass Filter Using Current-Sharing Vertical Differential Pairs
1
Issued Date
2025-01-01
Resource Type
ISSN
10638210
eISSN
15579999
Scopus ID
2-s2.0-85218901541
Journal Title
IEEE Transactions on Very Large Scale Integration (VLSI) Systems
Rights Holder(s)
SCOPUS
Bibliographic Citation
IEEE Transactions on Very Large Scale Integration (VLSI) Systems (2025)
Suggested Citation
Pawarangkoon P., Ahmad R., Zawawi R.A., Manaf A.A., Surakampontorn W., Thanapitak S. A Nanopower EEG Low-Pass Filter Using Current-Sharing Vertical Differential Pairs. IEEE Transactions on Very Large Scale Integration (VLSI) Systems (2025). doi:10.1109/TVLSI.2025.3540116 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/105540
Title
A Nanopower EEG Low-Pass Filter Using Current-Sharing Vertical Differential Pairs
Corresponding Author(s)
Other Contributor(s)
Abstract
A follower-based gm - C low-pass filter that employs CMOS vertical source-couple-pair (VSCP) transconductors is proposed for practical use in EEG acquisition systems. The VSCP transconductor operates as a gm cell with current sharing and linearity enhancement features. It is applied in the first-and second-order gm - C sections cascaded to form a third-order low-pass filter targeting a 150-Hz bandwidth. To mitigate the effects of biasing current source mismatch, dynamic element matching (DEM) is optionally applied to the relevant biasing current source pairs, resulting in second harmonic distortion (HD2) and noise suppression. Implemented in a 0.18-μm process, the proposed filter consumes 16.3-nW power from a 1.2-V supply. Thanks to the DEM and VSCPs, the filter achieves a 150-mVP linear input range measured at 1% total harmonic distortion (THD), whereas the input-referred noise of 43 μVrms is obtained leading to a filter dynamic range (DR) of 65.15 dB. Overall performance comparisons with other recent nanopower filters indicate that the figure of merit (FoM) of this proposed filter is comparable, while the linear input range is larger.