Journal of Low Power Electronics and Applications (Feb 2022)

Fully Differential Miller Op-Amp with Enhanced Large- and Small-Signal Figures of Merit

  • Anindita Paul,
  • Jaime Ramirez-Angulo,
  • Héctor Vázquez-Leal,
  • Jesús Huerta-Chua,
  • Alejandro Diaz-Sanchez

DOI
https://doi.org/10.3390/jlpea12010009
Journal volume & issue
Vol. 12, no. 1
p. 9

Abstract

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A highly power-efficient, fully differential Miller op-amp with accurately controlled output quiescent current is introduced. The op-amp can drive both capacitive and resistive load due to the presence of the auxiliary amplifier. This amplifier helps to achieve class AB operation of the proposed op-amp. The fully differential auxiliary amplifier is compact and uses a resistive local common-mode feedback network. It consumes only 6% of the total current of the op-amp. The proposed op-amp has several innovative features. Incorporating the auxiliary amplifier helps to improve the unity gain frequency, power efficiency, slew-rate, and common-mode rejection ratio of the proposed op-amp. It can drive a wide range of resistive (200 Ω–1 MΩ) and capacitive loads (5 pF–300 pF). The op-amp has a large signal dynamic current efficiency of 8.6 and a large signal static current efficiency of 7.9. The small-signal figure of merit is 8.7 for RL = 1 MΩ and 7.3 for RL = 200 Ω.

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