A sub-1V supply CMOS voltage reference generator

• Published in: International journal of circuit theory and applications Vol. 40; no. 8; pp. 745 - 758
• Main Authors: Tsitouras, A., Plessas, F., Birbas, M., Kikidis, J., Kalivas, G.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.08.2012
• Subjects: bandgap reference; low power; Power Supply Rejection Ratio (PSRR); robustness; sub-1V operation; temperature coefficient (TC); temperature range; temperature stability; weak inversion
• ISSN: 0098-9886; 1097-007X
• DOI: 10.1002/cta.753

SUMMARY An integrated sub‐1V voltage reference generator, designed in standard 90‐nm CMOS technology, is presented in this paper. The proposed voltage reference circuit consists of a conventional bandgap core based on the use of p‐n‐p substrate vertical bipolar devices and a voltage‐to‐current converter. The former produces a current with a positive temperature coefficient (TC), whereas the latter translates the emitter‐base voltage of the core p‐n‐p bipolar device to a current with a negative TC. The circuit includes two operational amplifiers with a rail‐to‐rail output stage for enabling stable and robust operation overall process and supply voltage variations while it employs a total resistance of less than 600 K Ω. Detailed analysis is presented to demonstrate that the proposed circuit technique enables die area reduction. The presented voltage reference generator exhibits a PSRR of 52.78 dB and a TC of 23.66ppm/∘C in the range of − 40 and 125∘C at the typical corner case at 1 V. The output reference voltage of 510 mV achieves a total absolute variation of ± 3.3% overall process and supply voltage variations and a total standard deviation, σ, of 4.5 mV, respectively, in the temperature range of − 36 and 125∘C. Copyright © 2011 John Wiley & Sons, Ltd. The proposed voltage reference consists of a conventional bandgap core and a voltage to current converter. The use of the voltage to current converter replaces one of the two equal large resistors in the classical sub‐1V voltage reference of Banba et al., and reduces the value of the resistor required for the generation of the complementary to absolute temperature current without sacrificing the circuit performance. The latter is proven through circuit analysis. Copyright © 2011 John Wiley & Sons, Ltd.