A 0.5 V Operational Transconductance Amplifier Based on Dynamic Threshold-Voltage MOSFET and Floating Gate MOSFET Inverters in 180 nm CMOS Technology

Subject Areas : Renewable energy

Amir Baghi Rahin ¹ , Vahid Baghi Rahin ²

1 - Department of Electrical Engineering- Sardroud Branch, Islamic Azad University, Sardroud, Tabriz, Iran
2 - Department of Electrical Engineering- Sardroud Branch, Islamic Azad University, Sardroud, Tabriz, Iran

Received: 2022-04-01 Accepted : 2022-08-01 Published : 2025-02-19

Keywords: low voltage and low power, dynamic threshold-voltage MOSFET, floating gate MOSFET transistor, operational transconductance amplifier,

Abstract :

This paper presents a fully differential operational transconductance amplifier (OTA) based on the dynamic threshold-voltage MOSFET and floating gate MOSFET (DT/FGMOS) inverter with a supply voltage of 0.5 V. The proposed inverter in the structure of this OTA is a combination of the dynamic threshold-voltage MOSFET (DTMOS) technique (for all PMOS transistors) and the floating gate MOSFET (FGMOS) (for all NMOS transistors) in n-well process. In this circuit, feedforward and feedback paths have been used to limit the common-mode gain. The first stage has feedforward paths to eliminate the common-mode and the second stage has the common-mode feedback to stabilize the common-mode output voltage on Vdd/2. Based on the post-layout simulation results, the proposed OTA showed a gain of 61 dB with a unity gain frequency (UGF) of 1.1 MHz under 13 pF load capacitors. With the studies performed by Monte Carlo analysis, it was found that the OTA based on the proposed inverter can perform well under process variations and device mismatches. The proposed circuit in 180 nm CMOS technology occupies an area of ​​0.182 mm2 from the chip. Its power consumption is 17 µW and it can be used in low voltage and low power applications including portable equipment. According to studies, the use of DTMOS and FGMOS techniques can lead to the effective reduction of the threshold voltage of transistors and the good performance of the proposed OTA at low voltage.

References:

[1] A.B. Rahin, Z.D.K. Kanani, “A low-voltage and low-power programmable Gm-C filter for wireless applications”, Journal of Intelligent Procedures in Electrical Technology, vol. 5, no. 19, pp. 3-10, Dec. 2014 (in Persian) (dor: 20.1001.1.23223871.1393.5.19.1.4).

[2] S.M.A. Zanjani, M. Parvizi, “Design and simulation of a bulk driven operational trans-conductance amplifier based on CNTFET technology”, Journal of Intelligent Procedures in Electrical Technology, vol. 12, no. 45, pp. 63-74, June 2021 (in Persian) (dor: 20.1001.1.23223871.1400.12.1.5.1).

[3] S.A. Zanjani, A. Jannesari, P. Torkzadeh, “Design and simulation of ultra-low-power sigma-delta converter using the fully differential inverter-based amplifier for digital hearing aids application”, Jou­rnal of Intelligent Procedures in Electrical Technology, vol. 13, no. 51, pp. 75-90, Dec. 2022 (in Persian) (dor: 20.1001.1.23223871.1401.13.51.5.8).

[4] R. Póvoa, A. Canelas, R. Martins, N. Horta, N. Lourenço, J. Goes, “A low noise CMOS inverter-based OTA for and healthcare signal receivers”, Proceeding of the IEEE/SMACD, pp. 1-4, Lausanne, Switzerland, July 2019 (doi: 10.1109/SMACD.2019.8795248).

[5] B. Nauta, “A CMOS transconductance-C filter technique for very high frequencies”, IEEE Journal of Solid-State Circuits, vol. 27, no. 2, pp. 142–153, Feb. 1992 (doi: 10.1109/4.127337).

[6] H. Barthélemy, S. Meill, J. Gaubert, N. Dehaese, S. Bourdel, “OTA based on CMOS inverter and application in the design of tunable bandpass filter”, Analog Integrated Circuits and Signal Processing, vol. 57, no. 2, pp. 169-178, Dec 2008 (doi: 10.1007/s10470-008-9167-8).

[7] F. Muñoz, A. Torralba, R.G. Carvajal, J. Tombs, J. Ramirez–Angulo, “Floating-gate-based tunable CMOS low voltage linear transconductor and its application to HF gm-C filter design”, IEEE Trans. on Circuits and Systems II, vol. 48, no. 1, pp. 106-110, May 2001 (doi: 10.1109/82.913194).

[8] S. Ramasamy, B. Venkataramani, “A low power reconfigurable analog baseband block for software defined radio”, Journal of Signal Processing System, vol. 62, no. 2, pp. 131–144, Feb. 2011 (doi: 10.1007/s11265-009-0357-0).

[9] K. Komoriyama, E. Yoshida, M. Yashiki, & H. Tanimoto, “A very wideband fully balanced active RC polyphase filter based on CMOS inverters in 0.18μm CMOS technology”, Proceeding of the IEEE/VLSIC, pp. 98-99, Kyoto, Japan, June 2007 (doi: 10.1109/VLSIC.2007.4342676).

[10] A. Tanaka, H. Tanimoto, “Design of 1 V operating fully differential OTA using NMOS inverters”, IEICE Transactions on Electronics, vol. 92, no. 6, pp.  822-827, June 2009 (doi: 10.1587/transele.E92.C.822).

[11] J. Sobhi, Z. Daei Koozeh Kanani, A. Baghi Rahin, A. Tahmasebi, “A new OTA based on FGMOS inverters for low voltage and low power applications”, Proceedings of the ICCSP, vol. 3, pp. 23-26, Jan. 2010.

[12] H. Tanimoto, K. Yazawa, M. Haraguchi, “A fully-differential OTA based on CMOS cascode inverters operating from 1-V power supply”, Springer, Analog Integrated Circuits and Signal Processing, vol. 78, no. 1, pp. 23–31, Jan. 2014 (doi: 10.1007/s10470-013-0126-7).

[13] A. Baghi Rahin, M.H. Ghasemi, V. Baghi Rahin, “DTMOS-based low-voltage and low-power two-stage OTA”, Proceeding of the IEEE/ETECH, pp. 685-690, Bangalore, India, March 2021 (doi: 10.1109/R­TEICT5­2294.2021.­9573559).

[14] A. Baghi Rahin, V. Baghi Rahin, “A new 2-input CNTFET-based XOR cell with ultra-low leakage power for low-voltage and low-power full adders”, Journal of Intelligent Procedures in Electrical Technology, vol. 10, no. 37, pp. 2322-3871, May 2019 (in Persian) (dor: 20.1001.1.23223871.1398.10.37.2.6).

[15] H. Liu, A.I. Karsilayan, “A high frequency bandpass continuous-time filter with automatic frequency and Q-factor tuning”, Proceeding of the IEEE/ISCAS, vol. 1, pp. 328–331, May 2001 (doi: 10.1109/ISCAS.2­001.9­21859).

[16] X. Zhang, E.I. EI-Masry, “A novel CMOS OTA based on body-driven MOSFETs and its applications in OTA-C filters”, IEEE Trans. on Circuits and Systems I: Fundamental Theory and Applications, vol. 54, no. 6, pp. 1204–1212, June 2007 (doi: 10.1109/TCSI.2007.897765).

[17] F. Assaderaghi, D. Sinitsky, S. A. Parke, J. Bokor, P. K. Ko and Chenming Hu, "Dynamic threshold-voltage MOSFET (DTMOS) for ultra-low voltage VLSI", IEEE Trans. on Electron Devices, vol. 44, no. 3, pp. 414-422, March 1997 (doi: 10.1109/16.556151).

[18] H. Kuntman, D. Özenli, “DTMOS-based ultra-low-voltage low-power circuit design. In: trends in circuit design for analog signal processing”, Trends in Circuit Design for Analog Signal Processing, pp. 267-283, May 2022 (doi: 10.1007/978-3-030-96836-6_11).

[19] M. Mahendra, S. Kumari, M. Gupta, “DTMOS based low power adaptively biased fully differential transconductance amplifier with enhanced slew-rate and its filter application”, IETE Journal of Research, May 2021 (doi: 10.1080/03772063.2021.1925599).

[20] E. Kargaran, M. Sawan, K. Mafinezhad, H. Nabovati, “Design of 0.4V, 386nW OTA using DTMOS technique for biomedical applications”, Proceeding of the IEEE/MWSCAS, pp. 270-273, Boise, ID, USA, Aug. 2012 (doi: 10.1109/MWSCAS.2012.6292009).

[21] M. Maymandi-Nejad and M. Sachdev, “DTMOS Technique for Low-Voltage Analog Circuits”, IEEE Trans. on Very Large Scale Integration Systems, vol. 14, no. 10, pp. 1151-1156, Oct. 2006 (doi: 10.110­9/TV­LSI.2­006.884174).

[22] E. Rodriguez-Villegas, "Low power and low voltage circuit design with the FGMOS transistor", IET, 2006 (ISBN: 9780863416170).

[23] J.F. Duque-Carrillo, J.L. Ausin, G. Torelli, J.M. Valverde, M.A. Domı´nguez, “1-V rail-to-rail operational amplifiers in standard CMOS technology”, IEEE Journal of Solid-State Circuits, vol. 35, no. 1, 33–44, Jan. 2000 (doi: 10.1109/4.818918).

[24] M. Kumngern, T. Kulej, F. Khateb, V. Stopjakova, R.K. Ranjan, “Nanopower multiple-input DTMOS OTA and its applications to high-order filters for biomedical systems”, AEU- International Journal of Electronics and Communications, vol. 130, Article Number: 153576, Feb. 2021 (doi: 10.1016/j.aeue.20­2­0.15­3576).   

[25] J. Wang, Y. Li, Z. Zhu, “A 0.6-V pseudo-differential OTA with switched-opamp technique for low power applications”, Microelectronics Journal, vol. 90, pp. 117–122, Aug. 2019 (doi: 10.1016/j.mejo.2­019.0­6.0­0­2­).

[26] F. Centurelli, A. Fava, M. Olivieri, P. Tommasino, A. Trifiletti, “A low-voltage class-ab ota exploiting adaptive biasing”, AEU-International Journal of Electronics and Communications, vol. 122, Article Number: 153282, July 2020 (doi: 10.1016/j.aeue.2020.153282).

[27] F. Rezaei, “0.3V tunable OTA and Gm-C filter in 0.13µm CMOS”, Transactions D: Computer Science and Engineering and Electrical Engineering, Scientia Iranica, vol. 28, no. 6, pp. 3333-3341, Dec. 2021 (doi: 10.24200/sci.2019.5452.1278).