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Design and Implementation of Reference-Free Drift-Cancelling CMOS Magnetic Sensors for Biosensing Applications

Sideris, Constantine and Khial, Parham P. and Hajimiri, Ali (2018) Design and Implementation of Reference-Free Drift-Cancelling CMOS Magnetic Sensors for Biosensing Applications. IEEE Journal of Solid-State Circuits, 53 (11). pp. 3065-3075. ISSN 0018-9200. doi:10.1109/JSSC.2018.2865480.

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Magnetic imagers, which utilize magnetic nanoparticles as labels to realize biodetection assays, hold significant promise for deployment at the point-of-use. Resonance-shift-based sensors can be realized in standard CMOS processes without post-process modifications and offer great sensitivity at low price tags. Unfortunately, CMOS resonant-shift magnetic sensors suffer significant degradation in SNR and long-term stability due to low on-chip inductor quality factors and significant noise introduced from active devices and thermal variations. This makes standard resonant-shift-based imagers undesirable for use in low-signal biodetection assays. Furthermore, and most importantly, the significant long-term drift due to slow-varying noise sources and temperature changes makes these sensors inadequate for bioexperiments which may take timescales on the order of hours to reach completion. In this paper, we propose a transformer-based approach which enables sub-parts-per-million (PPM) signal detection without the need for any thermal compensation. The approach is self-referencing, leading to significant savings in chip area by removing the need for replica reference cells. We analyze the performance of the transformer-based circuit compared to the original second-order system and demonstrate its superiority for rejecting system noise. A proof-of-concept design of a fully integrated 2×2 CMOS transformer-based magnetic sensor array is presented which achieves reference-free, sub-PPM detection of magnetic signals. The system can be powered and operated completely from a laptop USB interface and each sensing cell can consume less than 3 mW of DC power. Finally, we show the results of an initial DNA biodetection experiment which confirms the capability of the sensor to be used for realistic bioassays.

Item Type:Article
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URLURL TypeDescription
Sideris, Constantine0000-0002-3042-4889
Khial, Parham P.0000-0002-3242-8541
Hajimiri, Ali0000-0001-6736-8019
Additional Information:© 2018 IEEE. Manuscript received May 4, 2018; revised July 12, 2018; accepted July 27, 2018. Date of publication October 11, 2018; date of current version October 22, 2018. This paper was approved by Guest Editor Chung-Yu Wu. The authors would like to thank B. Ling for help with wet-lab experiments, B. Hong for help with layout, and K. Mauser and N. Scianmarello for help with sample preparation.
Subject Keywords:Chemical and biological sensors, CMOS integrated circuits, drift cancelling, magnetic sensors, medical diagnostics, point of care (PoC), point of use (PoU), reference free
Issue or Number:11
Record Number:CaltechAUTHORS:20181023-151906461
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Official Citation:C. Sideris, P. P. Khial and A. Hajimiri, "Design and Implementation of Reference-Free Drift-Cancelling CMOS Magnetic Sensors for Biosensing Applications," in IEEE Journal of Solid-State Circuits, vol. 53, no. 11, pp. 3065-3075, Nov. 2018. doi: 10.1109/JSSC.2018.2865480
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90383
Deposited By: Tony Diaz
Deposited On:23 Oct 2018 22:27
Last Modified:16 Nov 2021 03:32

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