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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