An amplifier circuit includes multiple transistors, a set of input routing circuits, and a set of output routing circuits. Each output routing circuit corresponds to an input routing circuit. Each input routing circuit and its corresponding output routing circuit are controlled by one or more control signals. Each input routing circuit is configured to selectively connect each transistor of a transistor pair to a first input terminal of the amplifier circuit, a second input terminal of the amplifier circuit, or a third input terminal of the amplifier based on a value of the one or more control signals. Each output routing circuit is configured to selectively connect each transistor of the transistor pair to a first output terminal of the amplifier circuit, a second output terminal of the amplifier circuit, or a calibration circuit based on the value of the one or more control signals.