Abstract
In this paper, two programmable operational transconductance amplifiers (POTAs)—one using bulk driven attenuator (BDA) and another using programmable current mirror (PCM) are proposed in order to achieve low-Gm and high dynamic range. These OTAs are denoted as BDA-POTA and PCM-OTA respectively and are realized using composite transistors operated in the subthreshold region. The pseudo resistor is used for achieving programmability in the former and for improving the linearity and dynamic range in the latter. The proposed OTAs and two 4th order programmable Butterworth low pass filters (LPF) are designed and implemented in CMOS 180 nm technology with a supply voltage of 0.9 V. Their performances are evaluated through post-layout simulations and are found to be superior compared to those of POTAs reported in the literature for biomedical applications. The power consumption, transconductance, dynamic range and input-referred noise of BDA-POTA and PCM-OTA are [25.2 nW, (7.89–15.61 nS), (77.54–74.89 dB), (39.86–51.19 µVrms)] and [72.81 nW, (5.49–174.5 nS), (91.20–84.39 dB), (17.19–34.92 µVrms)] respectively. The power dissipation and cut off frequency range of the LPF using BDA-POTA and PCM-OTA are [197.8 nW, (30–100 Hz)] and [209.8 nW, (16–971 Hz)] respectively. The latter achieves 13.6 times wider programmability with only 5% increase in power dissipation. The proposed LPFs have better FOM compared to those reported in the literature.
Similar content being viewed by others
References
Li, Y., Poon, C. C. Y., & Zhang, Y. (2010). Analog integrated circuits design for processing physiological signals. IEEE Reviews in Biomedical Engineering, 3, 93–105.
Lee, S. Y., & Cheng, C. J. (2009). Systematic design and modeling of an OTA-C filter for portable ECG detection. IEEE Transactions on Biomedical Circuits and Systems, 3, 53–64.
Harrison, R. R. (2008). The design of integrated circuits to observe brain activity. Proceedings of the IEEE, 96(7), 1203–1216.
Sanjay, R., Senthil Rajan, V., & Venkataramani, B. (2018). A low-power low-noise and high swing biopotential amplifier in 0.18 μm CMOS. Analog Integrated Circuits and Signal Processing, 96(3), 565–576.
Elamien, M. B., & Mahmoud, S. A. (2017). Analysis and design of a highly linear CMOS OTA for portable biomedical applications in 90 nm CMOS. Microelectronics Journal, 70, 72–80.
Shiue, M., Yao, K., Gong, C., et al. (2011). Tunable high resistance voltage controlled pseudo-resistor with wide input voltage swing capability. Electronics Letters, 47, 377.
Tajalli, A., & Leblebici, Y. (2012). Power and area efficient MOSFET-C filter for very low frequency applications. Analog Integrated Circuits and Signal Processing, 70, 123.
Lee, S.-Y., Wang, C.-P., & Chu, Y.-S. (2019). Low-voltage OTA-C filter with an area and power-efficient OTA for bio signal sensor applications. IEEE Transactions on Biomedical Circuits and Systems, 13(1), 56–67.
Alhammadi, A. A., & Mahmoud, S. A. (2016). Fully differential fifth-order dual-notch power line interference filter oriented to EEG detection system with low pass feature. Microelectronics Journal, 56, 122–133.
Lee, S. Y., & Cheng, C. J. (2009). Systematic design and modelling of an OTA-C filter for portable ECG detection. IEEE Transactions on Biomedical Circuits and Systems, 3(1), 53–64.
Stotts, L. J. (1989). Introduction to implantable biomedical IC design. IEEE Circuits and Devices Magazine, 5(1), 12–18.
Seok, C., Lim, K., Seo, J., Kim, H., Im, S., Kim, J.-H., et al. (2013). Area-efficient RC low pass filter using T-networked resistors and capacitance multiplier. In 2013 13th International Conference on Control Automation and Systems (ICCAS), pp. 1308–1311.
Solís-Bustos, S., Silva-Martínez, J., Maloberti, F., & Sánchez-Sinencio, E. (2000). A 60 dB dynamic-range CMOS sixth-order 2.4 Hz lowpass filter for medical applications. IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing Conference, 47, 1391–1398.
Senthil Rajan, V., Sanjay, R., Kumaravel, S., & Venkataramani, B. (2019). Area and power efficient flipped voltage follower based symmetrical floating impedance scaler with improved accuracy for fully differential filters. AEU International Journal of Electronics and Communications, 106, 116–125.
Senthil Rajan, V., Sanjay, R., Hari Kishore, K., & Venkataramani, B. (2020). A cross-coupled symmetric floating impedance scaler with enhanced bandwidth and accuracy. AEU International Journal of Electronics and Communications, 122, 153242.
Silva-Martinez, J., & Salcedo-Suñer, J. (1997). IC voltage to current transducers with very small transconductance. Analog Integrated Circuits and Signal Processing, 13(3), 285–293.
Silva-Martinez, J., & Solis-Bustos, S. (1999). Design considerations for high performance very low frequency filters. In ISCAS’99. Proceedings of the 1999 IEEE international symposium on circuits and systems VLSI (Cat. No. 99CH36349), Vol. 2, pp. 648–651.
Solís-Bustos, S., Silva-Martínez, J., Maloberti, F., & Sánchez-Sinencio, E. (2000). A 60-dB dynamic-range CMOS sixth-order 2.4-Hz lowpass filter for medical applications. IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, 47, 1391.
Silva-Martinez, J., & Salcedo-Suñer, J. (1997). IC voltage to current transducers with very small transconductance. Analog Integrated Circuits and Signal Processing, 13, 285.
Rodriguez-Villegas, E., Yúfera, A., & Rueda, A. (2004). A 1.25-V micropower Gm-C filter based on FGMOS transistors operating in weak inversion. IEEE Journal of Solid-State Circuits, 39, 100.
Mourabit, A., Lu, G.-N., & Pittet, P. (2005). Wide-linear-range subthreshold OTA for low-power, low-voltage and low-frequency applications. IEEE Transactions on Circuits and Systems I: Regular Papers, 52, 1481.
Chawla, R., Adil, F., Serrano, G., & Hasler, P. E. (2007). Programmable Gm-C filters using floating-gate operational transconductance amplifiers. IEEE Transactions on Circuits and Systems I: Regular Papers, 54(3), 481–491.
Soares, Carlos F. T., de Moraes, G. S., & Petraglia, A. (2014). A low-transconductance OTA with improved linearity suitable for low-frequency Gm-C filters. Microelectronics Journal, 45(11), 1499–1507.
Moreno, Ricardo F. L., Baruqui, Fernando A. P., & Petraglia, A. (2015). Bulk-tuned Gm-C filter using current cancellation. Microelectronics Journal, 46, 777–782.
Sawigun, C., & Serdijn, W. A. (2012) A modular transconductance reduction technique for very low-frequency Gm-C filters. In IEEE International Symposium on Circuits and Systems (ISCAS), pp. 1183–1186.
Kongpoon, M. (2013). A novel OTA-based voltage attenuation technique for very low frequency filtering using low-Gm OTA filters. In International symposium on intelligent signal processing and communication systems, pp. 680–683.
Thanapitak, S. (2014). An 1-V, 74-dB, sub-Hz Gm-C filter based on a modular transconductance reduction technique. In 11th International conference on electrical engineering electronics, computer, telecommunications and information technology, pp. 2–5.
Thanapitak, S. (2015). OTA-C differentiator for large time constant applications. In 12th international conference on electrical engineering/electronics, computer, telecommunications and information technology, pp. 1–4.
Senthil Rajan, V., Kakara, H., Sanjay, R., Kumaravel, S., & Venkataramani, B. (2020). A novel programmable attenuator based low Gm-OTA for biomedical applications. Microelectronics Journal, 97, 104721.
Mahmoud, S. A., Bamakhramah, A., & Al-Tunaiji, S. A. (2013). Low noise low pass filter for ECG portable detection systems with digitally programmable range. Circuits, Systems, and Signal Processing, 32(5), 2029–2045.
Hanumantha, G., & Rekha, S. (2018). Low voltage, low power Gm-C filter for low frequency applications. Journal of Low Power Electronics, 14, 266–274.
Igarashi, Y., Hyogo, A., & Sekine, K. (1994). Design of very lowdistortion, four-quadrant analog multiplier-type CMOS-OTA considering variation of mobility according to the gate voltage. Electronics and Communications in Japan (Part II: Electronics), 77(7), 65–76.
Veeravalli, A., Sánchez-Sinencio, E., & Silva-Martínez, J. (2005). A CMOS transconductance amplifier architecture with wide tuning range for very low frequency applications. IEEE Journal of Solid-State Circuits, 37(6), 776–781.
Gray, P. R., Hurst, P. J., Lewis, S. H., & Meyer, R. G. (2009). Analysis and design of analog integrated circuits (5th ed.). Hoboken: Wiley.
Gosselin, B., Sawan, M., & Kerherve, E. (2010). Linear-phase delay filters for ultra-low-power signal processing in neural recording implants. IEEE Transactions on Biomedical Circuits and Systems, 4(3), 171–180.
Elamien, M. B., & Mahmoud, S. A. (2018). On the design of highly linear CMOS digitally programmable operational transconductance amplifiers for low and high frequency applications. Analog Integrated Circuits and Signal Processing, 97, 225–241.
Rezaei, F., & Azhari, S. J. (2011). Ultra low voltage, high performance operational transconductance amplifier and its application in a tunable Gm-C filter. Microelectronics Journal, 42, 827–836.
Pinto, P. M., Ferreira, Luís H. C., Colletta, G. D., & Braga, Rodrigo A. S. (2019). A 0.25-V fifth-order Butterworth low-pass filter based on fully differential difference transconductance amplifier architecture. Microelectronics Journal, 92, 104606.
Krishna, J. R. M., & Laxminidhi, T. (2019). Widely tunable low-pass gm-C filter for biomedical applications. IET Circuits, Devices and Systems, 13, 239–244.
Sun, C. Y., & Lee, S. Y. (2018). Fifth-order butter worth OTA-C LPF with multiple-output differential-input OTA for ECG applications. IEEE Transactions on Circuits and Systems II: Express Briefs, 65, 421–425.
Rakhi, R., Taralkar, A. D., Vasantha, M. H., & YB, N. K. (2017). A 0.5 V low power OTA-C low pass filter for ECG detection. In IEEE Computer Society annual symposium on VLSI (ISVLSI), pp. 589–593.
Arya, R., & Oliveira, J. P. (2016). Gm-C biquad filter for low signal sensor applications. In 2016 MIXDES-23rd international conference mixed design of integrated circuits and systems, pp. 207–210.
Chart-O-Matic: View Signals and Annotations, PhysioNet, created by MIT Room E25-505A. http://www.physionet.org/cgi-bin/chart.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Rajan, V.S., Venkataramani, B. Design of low power, programmable low-Gm OTAs and Gm-C filters for biomedical applications. Analog Integr Circ Sig Process 107, 389–409 (2021). https://doi.org/10.1007/s10470-020-01748-0
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10470-020-01748-0