An operational amplifier includes a differential input stage (30) having first (2) and second (3) input conductors, a class AB output stage (20) coupled to an output of the differential input stage (30) and including a pull-up transistor (M11) having a source coupled to a first supply voltage (VDD), a drain coupled to an output conductor (17), and a gate coupled to a first terminal (14) of a class AB control circuit (11), and a pull-down transistor (M12) having a source coupled to a second supply voltage (GND), a drain coupled to the output conductor (17), and a gate coupled to a second terminal (15) of the class AB control circuit (11). A differential input signal is applied between the first (2) and second (3) input conductors, and simultaneously also is applied between first and second inputs of a first unbalanced differential amplifier (31) and between first and second input to the second unbalanced differential amplifier (32). If the differential input signal is of a first polarity and is of a magnitude substantially greater than a threshold voltage of the first unbalanced differential amplifier (31), the magnitude of a turn-on voltage of the pull-down transistor (M12) is decreased and the magnitude of a turn-on voltage of the pull-up transistor (M11) is increased in response to an output voltage produced by the first unbalanced differential amplifier (31). However, if the differential input signal is of a second polarity and is of a magnitude substantially greater than a threshold voltage of the second unbalanced differential amplifier (32), then the magnitude of a turn-on voltage of the pull-up transistor (M11) is increased and the magnitude of a turn-on voltage of the pull-down transistor (M12) is simultaneously decreased, in response to an output voltage produced by the second unbalanced differential amplifier (32).