The paper is available at the following link: PDF

Abstract:

This paper presents a precision CMOS bandgap reference with an integrated autocalibration mechanism, implemented in the TSMC 65 nm GP process. The circuit operates from dual supply voltages of 1.8 V for analog and 1.2 V for digital domains, consuming 1.064 mW across the temperature range of – 40 °C to 125 °C and occupying area of 0.066 mm2. It provides a 1.2265 V ± 8.5 mV (3σ) bandgap output, a 1 V reference, and proportional-to-absolute-temperature (PTAT) and zero- temperature-coefficient (ZTAT) reference currents. The autocalibration algorithm adjusts internal PTAT currents using an external precision resistor as a calibration standard, effectively compensating for process variations without manual trimming. Simulation results demonstrate high stability, low temperature dependence, and improved process robustness, making the circuit suitable for high precision mixed-signal systems-on-chip applications.

Keywords:

Bandgap reference, CMOS, process variation compensation, autocalibration, analog CMOS design, TSMC 65nm technology.

REFERENCES:

[1] [1] R. Widlar, "New developments in IC voltage regulators," 1970 IEEE International Solid-State Circuits Conference. Digest of Technical Papers, Philadelphia, PA, USA, 1970, pp. 158-159
[2] H. Ray Alan, "The Art of Analog Layout", 1st. Prentice Hall, Upper Saddle River, NJ, 2001.
[3] G. A. Rincon-Mora, "Voltage References: From Diodes to Precision High-Order Bandgap Circuits", 1st. Wiley- IEEE Press, 2001
[4] C. Toumazou, G. S. Moschytz i B. Gilbert, "Trade-offs in analog circuit design: the designer's companion." Boston: Kluwer Academic Publishers, 2002.
[5] P. E. Allen and D. R. Holberg, "CMOS analog circuit design" (Oxford series in electrical and computer engineering), 2nd. New York: Oxford University Press, 2010.
[6] K. Chi-Wah i T. Wing-Shan, "CMOS Voltage References", 1st. Wiley, 2013
[7] B. Razavi, "Fundamentals of microelectronics", 2nd. Wiley, 2013.
[8] B. Razavi, "Design of analog CMOS integrated circuits", 2nd. New York, NY: McGraw-Hill Education, 2017.
[9] Z. Jun-an et al., "A bandgap reference in 65nm CMOS," 2016 IEEE International Nanoelectronics Conference (INEC), Chengdu, China, 2016, pp. 1-2
[10] P. Kinget, C. Vezyrtzis, E. Chiang, B. Hung and T. L. Li, "Voltage references for ultra-low supply voltages," 2008 IEEE Custom Integrated Circuits Conference, San Jose, CA, USA, 2008, pp. 715-720
[11] K. N. Leung and P. K. T. Mok, "A sub-1-V 15-ppm/oC CMOS bandgap voltage reference without requiring low threshold voltage device," IEEE J. Solid-State Circuits, vol. 37, no. 4, pp. 526–530, Apr. 2002.
[12] H. Banba et al., "A CMOS bandgap reference circuit with sub-1-V operation," in IEEE Journal of Solid-State Circuits, vol. 34, no. 5, pp. 670-674, May 1999.
[13] C. -W. U, M. -K. Law, R. P. Martins and C. -S. Lam, "Sub-µW Auto-Calibration Bandgap Voltage Reference With 1σ Inaccuracy of ± 0.12% Within − 40°C to 120°C," in IEEE Journal of Solid-State Circuits, vol. 59, no. 2, pp. 540-550, Feb. 2024.