An operational amplifier is provided. The operational amplifier includes a first transistor configured to receive a first input voltage, a second transistor configured to receive a second input voltage, and a current steering module coupled to first and second transistors and configured to receive a reference voltage. The first and second transistors form a differential pair. The first transistor, second transistor, and current steering module are configured such that a current is steered from the current steering module or to the current steering module based on common-mode voltages of the first and second input voltages and the reference voltage to set a common-mode output voltage of the operational amplifier.