{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T21:10:25Z","timestamp":1792789825321,"version":"4.5.0"},"reference-count":37,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2021,4,3]],"date-time":"2021-04-03T00:00:00Z","timestamp":1617408000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of science and innovation of Spain- Neuroware project","award":["PGC2018-097339"],"award-info":[{"award-number":["PGC2018-097339"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>There are emerging applications, like bridge structural health monitoring, continuous patient condition and outdoor aiding of the elderly and the disabled, where Internet of things (IoT) nodes are used with very limited accessibility and no connection to the main supply network. They may also be exposed to harsh environmental conditions. These are applications where power and available area constraints are of great concern. In this paper, we design a 1.1 V low dropout (LDO) linear regulator in 40 nm technology to be embedded in IoT nodes. To address these constraints, we used state-of-the-art, variability-aware resistor-less sub-threshold biased CMOS-only ultra low power consumption configurations having low active area. The proposed LDO is internally compensated with embedded 18 pF Miller and 10 pF load capacitances. It can supply 1 mA maximum load current with 0.8 uA quiescent current. The dropout voltage of the regulator is 200 mV with minimum input voltage of 1.3 V. The efficiency of the regulator is 84%, which is about 99% of the maximum achievable efficiency for a 200 mV dropout voltage. The whole circuit, consisting of the embedded voltage reference and the Miller and load capacitances, takes less than 0.007 mm2 of the die size with 1 \u03bcW power consumption.<\/jats:p>","DOI":"10.3390\/mi12040396","type":"journal-article","created":{"date-parts":[[2021,4,3]],"date-time":"2021-04-03T22:03:36Z","timestamp":1617487416000},"page":"396","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["An RFID-Based Self-Biased 40 nm Low Power LDO Regulator for IoT Applications"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1307-3498","authenticated-orcid":false,"given":"Asghar","family":"Bahramali","sequence":"first","affiliation":[{"name":"IPTC, ETSI Telecomunicaci\u00f3n, Universidad Polit\u00e9cnica de Madrid, Avda. Complutense 30, 28040 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3833-524X","authenticated-orcid":false,"given":"Marisa","family":"Lopez-Vallejo","sequence":"additional","affiliation":[{"name":"IPTC, ETSI Telecomunicaci\u00f3n, Universidad Polit\u00e9cnica de Madrid, Avda. Complutense 30, 28040 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,4,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1016\/j.bjp.2013.12.020","article-title":"SmartSantander: IoT experimentation over a smart city testbed","volume":"61","author":"Ramdhany","year":"2014","journal-title":"Comput. Netw."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Tong, X., Yang, H., Wang, L., and Miao, Y. (2019). The development and field evaluation of an IoT system of low-power vibration for bridge health monitoring. Sensors, 19.","DOI":"10.3390\/s19051222"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Tang, X., Wang, X., Cattley, R., Gu, F., and Ball, A.D. (2018). Energy harvesting technologies for achieving self-powered wireless sensor networks in machine condition monitoring: A review. Sensors, 18.","DOI":"10.3390\/s18124113"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Finkenzeller, K. (2010). RFID Handbook: Fundamentals and Applications in Contactless Smart Cards, Radio Frequency Identification and Near-Field Communication, John Wiley & Sons.","DOI":"10.1002\/9780470665121"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1109\/JIOT.2014.2313981","article-title":"RFID technology for IoT-based personal healthcare in smart spaces","volume":"1","author":"Amendola","year":"2014","journal-title":"IEEE Internet Things J."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"108","DOI":"10.1109\/MMM.2014.2309499","article-title":"Harvesting wireless power: Survey of energy-harvester conversion efficiency in far-field, wireless power transfer systems","volume":"15","author":"Valenta","year":"2014","journal-title":"IEEE Microw. Mag."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Heidrich, J., Brenk, D., Essel, J., Heinrich, M., Jung, M., Hofer, G., Holweg, G., Weigel, R., and Fischer, G. (2010, January 11\u201315). Design of a low-power voltage regulator for RFID applications. Proceedings of the 2010 IEEE Region 8 International Conference on Computational Technologies in Electrical and Electronics Engineering (SIBIRCON), Irkutsk, Russia.","DOI":"10.1109\/SIBIRCON.2010.5555135"},{"key":"ref_8","unstructured":"Black-Schaffer, D. (2015). Green Governors: A Framework for Continuously Adaptive DVFS, Uppsala University."},{"key":"ref_9","first-page":"245","article-title":"A low-power high-PSRR low-dropout regulator with bulk-gate controlled circuit","volume":"57","author":"Heng","year":"2010","journal-title":"IEEE Trans. Circuits Syst. II Express Br."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Yosef-Hay, Y., Muntal, P.L., Larsen, D.O., and J\u00f8rgensen, I.H. (2016, January 1\u20132). Capacitor-free, low drop-out linear regulator in a 180 nm CMOS for hearing aids. Proceedings of the 2016 IEEE Nordic Circuits and Systems Conference (NORCAS), Copenhagen, Denmark.","DOI":"10.1109\/NORCHIP.2016.7792888"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Bansal, N., and Gupta, R. (2018, January 6\u201310). An NMOS Low Drop-out Voltage Regulator with-17dB Wide-Band Power Supply Rejection for SerDes in 22FDX. Proceedings of the VLSI Design and 17th International Conference on Embedded Systems (VLSID), Pune, India.","DOI":"10.1109\/VLSID.2018.87"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"B\u00eez\u00eeitu, F., Serban, M.I., and Murtaza, C. (2014, January 13\u201315). On-chip 500 \u03bcA dual-chain Dickson charge pump optimized for NMOS LDO supply. Proceedings of the 2014 International Semiconductor Conference (CAS), Sinaia, Romania.","DOI":"10.1109\/SMICND.2014.6966443"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"272","DOI":"10.1016\/j.mejo.2014.01.010","article-title":"A CMOS fast transient response low-dropout regulator with a compact NMOS output driver","volume":"45","author":"Boas","year":"2014","journal-title":"Microelectron. J."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"You, K., Kim, S.H., and Choi, H. (2020). A Class-J Power Amplifier Implementation for Ultrasound Device Applications. Sensors, 20.","DOI":"10.3390\/s20082273"},{"key":"ref_15","unstructured":"Razavi, B. (2005). Design of Analog CMOS Integrated Circuits, McGraw Hill."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"703","DOI":"10.1109\/82.686689","article-title":"Optimized frequency-shaping circuit topologies for LDOs","volume":"45","author":"Allen","year":"1998","journal-title":"IEEE Trans. Circuits Syst. II Analog. Digit. Signal Process."},{"key":"ref_17","first-page":"1","article-title":"How to Successfully Apply Low-Dropout Regulators","volume":"43","author":"Marasco","year":"2009","journal-title":"Analog. Dialogue"},{"key":"ref_18","unstructured":"Morita, G. (2011). Noise sources in low dropout (LDO) regulators. Analog Devices Application Note AN-1120, Analog Devices Inc."},{"key":"ref_19","unstructured":"Lee, B.S. (1999). Understanding the Terms and Definitions of LDO Voltage Regulators, Texas Instruments Inc.. Texas Instrument Application Report SLVA079."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Khan, D., Abbasizadeh, H., Khan, Z.H.N., Park, Y.J., and Lee, K.Y. (2017, January 5\u20138). Design of a capacitor-less LDO with high PSRR for RF energy harvesting applications. Proceedings of the 2017 International SoC Design Conference (ISOCC), Seoul, Korea.","DOI":"10.1109\/ISOCC.2017.8368852"},{"key":"ref_21","unstructured":"(1999). Technical Review of Low Dropout Voltage Regulator Operation and Performance, Texas Instruments Inc.. Texas Instruments Application Report, SLVA072."},{"key":"ref_22","unstructured":"Ott, H.W. (1988). Noise Reduction Techniques in Electronic Systems, Wiley."},{"key":"ref_23","first-page":"1","article-title":"Understand low-dropout regulator (LDO) concepts to achieve optimal designs","volume":"48","author":"Morita","year":"2014","journal-title":"Analog. Dialogue"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"719","DOI":"10.1109\/JSSC.2019.2960004","article-title":"A Dynamically High-Impedance Charge-Pump-Based LDO With Digital-LDO-Like Properties Achieving a Sub-4-fs FoM","volume":"55","author":"Wang","year":"2019","journal-title":"IEEE J. Solid State Circuits"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Shirmohammadli, V., Saberkari, A., Martinez-Garcia, H., and Alarc\u00f3n-Cot, E. (2017, January 28\u201331). Low power output-capacitorless class-AB CMOS LDO regulator. Proceedings of the 2017 IEEE International Symposium on Circuits and Systems (ISCAS), Baltimore, MD, USA.","DOI":"10.1109\/ISCAS.2017.8050958"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Li, Q., Wang, K., and Zhao, J. (2019, January 12\u201314). A Capacitor-less LDO with Fast transient response using Push-Pull Buffer. Proceedings of the 2019 IEEE International Conference on Electron Devices and Solid-State Circuits (EDSSC), Xi\u2019an, China.","DOI":"10.1109\/EDSSC.2019.8753937"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Khan, M., and Chowdhury, M.H. (2018, January 27\u201330). Capacitor-less low-dropout regulator (LDO) with improved psrr and enhanced slew-rate. Proceedings of the 2018 IEEE International Symposium on Circuits and Systems (ISCAS), Florence, Italy.","DOI":"10.1109\/ISCAS.2018.8351039"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Asefi, S., Saberkari, A., Martinez-Garcia, H., and Alarcon, E. (2018, January 27\u201330). Low-Quiescent Current Class-AB CMOS LDO Voltage Regulator. Proceedings of the 2018 IEEE International Symposium on Circuits and Systems (ISCAS), Florence, Italy.","DOI":"10.1109\/ISCAS.2018.8351006"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1691","DOI":"10.1109\/JSSC.2003.817256","article-title":"A capacitor-free CMOS low-dropout regulator with damping-factor-control frequency compensation","volume":"38","author":"Leung","year":"2003","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Bahramali, A., and Lopez-Vallejo, M. (2018, January 2\u20134). A Temperature Variation Tolerant CMOS-Only Voltage Reference for RFID Applications. Proceedings of the 28th International Symposium on Power and Timing Modeling, Optimization and Simulation (PATMOS), Platja d\u2019Aro, Spain.","DOI":"10.1109\/PATMOS.2018.8464164"},{"key":"ref_31","unstructured":"Shao, Y., Wang, Y., Ning, Z., and He, L. (2009, January 20\u201323). Analysis and design of high power supply rejection LDO. Proceedings of the 2009 IEEE 8th International Conference on ASIC, Changsha, China."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1041","DOI":"10.1109\/TCSI.2004.829239","article-title":"A frequency compensation scheme for LDO voltage regulators","volume":"51","author":"Chava","year":"2004","journal-title":"IEEE Trans. Circuits Syst. I Regul. Pap."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1016\/j.vlsi.2019.01.014","article-title":"A low power RFID based energy harvesting temperature resilient CMOS-only reference voltage","volume":"67","author":"Bahramali","year":"2019","journal-title":"VLSI Integr."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Bahramali, A., Lopez-Vallejo, M., and Barrio, C.L. (2019, January 20\u201322). A 365 mv, 13 nw cmos-only energy harvested reference voltage for rfid applications in 40 nm technology. Proceedings of the 2019 XXXIV Conference on Design of Circuits and Integrated Systems (DCIS), Bilbao, Spain.","DOI":"10.1109\/DCIS201949030.2019.8959909"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Hinojo, J.M., Mart\u00ednez, C.L., and Torralba, A. (2018). Internally Compensated LDO Regulators for Modern System-on-Chip Design, Springer.","DOI":"10.1007\/978-3-319-75411-6"},{"key":"ref_36","unstructured":"Motchenbacher, C.D., and Connelly, J.A. (1993). Low Noise Electronic System Design, Wiley."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Liu, P., Huang, S., Duan, Q., Zhu, Q., and Meng, Z. (2019, January 12\u201314). A Low-Quiescent Current Off-Chip Capacitor-less LDO Regulator with UGCC Compensation. Proceedings of the 2019 IEEE International Conference on Electron Devices and Solid-State Circuits (EDSSC), Xi\u2019an, China.","DOI":"10.1109\/EDSSC.2019.8754106"}],"container-title":["Micromachines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-666X\/12\/4\/396\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T13:58:17Z","timestamp":1760363897000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-666X\/12\/4\/396"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,4,3]]},"references-count":37,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2021,4]]}},"alternative-id":["mi12040396"],"URL":"https:\/\/doi.org\/10.3390\/mi12040396","relation":{},"ISSN":["2072-666X"],"issn-type":[{"value":"2072-666X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,4,3]]}}}