15-nW biopotential LPFs in 0.35-μm CMOS using subthreshold-source- follower Biquads with and without gain compensation | |
Tan-Tan Zhang1; Pui-In Mak2![]() ![]() ![]() ![]() ![]() ![]() | |
2013-10 | |
Source Publication | IEEE Transactions on Biomedical Circuits and Systems
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ISSN | 1932-4545 |
Volume | 7Issue:5Pages:690-702 |
Abstract | Most biopotential readout front-ends rely on the g-C lowpass filter (LPF) for forefront signal conditioning. A small g realizes a large time constant (τ = C/g) suitable for ultra-low-cutoff filtering, saving both power and area. Yet, the noise and linearity can be compromised, given that each g cell can involve one or several noisy and nonlinear V-I conversions originated from the active devices. This paper proposes the subthreshold-source-follower (SSF) Biquad as a prospective alternative. It features: 1) a very small number of active devices reducing the noise and nonlinearity footsteps; 2) No explicit feedback in differential implementation, and 3) extension of filter order by cascading. This paper presents an in-depth treatment of SSF Biquad in the nW-power regime, analyzing its power and area tradeoffs with gain, linearity and noise. A gain-compensation (GC) scheme addressing the gain-loss problem of NMOS-based SSF Biquad due to the body effect is also proposed. Two 100-Hz 4th-order Butterworth LPFs using the SSF Biquads with and without GC were fabricated in 0.35-μm CMOS. Measurement results show that the non-GC (GC) LPF can achieve a DC gain of -3.7 ~dB (0 dB), an input-referred noise of 36 μV (29 μV ), a HD3@60 Hz of -55.2 ~dB (- 60.7 ~dB) and a die size of 0.11 mm (0.08 mm). Both LPFs draw 15 nW at 3 V. The achieved figure-of-merits (FoMs) are favorably comparable with the state-of-the-art. © 2007-2012 IEEE. |
Keyword | Biomedical Biopotential Body Effect Cmos Gain Compensation Harmonic Distortion Lowpass Filter Mosfet Source Follower Subthreshold Time Constant Transconductor |
DOI | http://doi.org/10.1109/TBCAS.2013.2238233 |
URL | View the original |
Indexed By | SCI |
Language | 英语 |
WOS Research Area | Engineering |
WOS Subject | Engineering, Biomedical ; Engineering, Electrical & Electronic |
WOS ID | WOS:000326622800015 |
Fulltext Access | |
Citation statistics | |
Document Type | Journal article |
Collection | DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING INSTITUTE OF MICROELECTRONICS |
Corresponding Author | Pui-In Mak |
Affiliation | 1.Biomedical Engineering Laboratory, FST-ECE, University of Macau, Macao 999078, China 2.State Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE, University of Macau, Macao 999078, China 3.Instituto Superior Técnico (IST)/TU of Lisbon, 1049-001 Lisbon, Portugal |
First Author Affilication | University of Macau |
Corresponding Author Affilication | University of Macau |
Recommended Citation GB/T 7714 | Tan-Tan Zhang,Pui-In Mak,Mang-I Vai,et al. 15-nW biopotential LPFs in 0.35-μm CMOS using subthreshold-source- follower Biquads with and without gain compensation[J]. IEEE Transactions on Biomedical Circuits and Systems,2013,7(5):690-702. |
APA | Tan-Tan Zhang.,Pui-In Mak.,Mang-I Vai.,Peng-Un Mak.,Man-Kay Law.,...&Rui P. Martins.(2013).15-nW biopotential LPFs in 0.35-μm CMOS using subthreshold-source- follower Biquads with and without gain compensation.IEEE Transactions on Biomedical Circuits and Systems,7(5),690-702. |
MLA | Tan-Tan Zhang,et al."15-nW biopotential LPFs in 0.35-μm CMOS using subthreshold-source- follower Biquads with and without gain compensation".IEEE Transactions on Biomedical Circuits and Systems 7.5(2013):690-702. |
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