The present disclosure relates to a full-bridge class D amplifier comprising a first and second half-bridge circuit, wherein each half-bridge comprises a half-bridge output terminal between a high-side switch and a low-side switch. Wherein the first and second half-bridge circuits are controlled by a respective control signal to operate in differential mode with a predetermined switching frequency and wherein each half-bridge circuit further comprises an output terminal inductor connected between the half-bridge output terminal and ground. The amplifier further comprises a first and second coil coupled to form a common mode choke, wherein the first half-bridge output terminal is connected to an input terminal of the first coil, and wherein the second half-bridge output terminal is connected to an input terminal of the second coil .

An apparatus comprises a plurality of selectable gain stages connected in parallel between a first bias voltage and ground, wherein each selectable gain stage comprises an amplification portion and a current steering portion, and wherein the current steering portion comprises a first selectable signal path connected between an output of the amplification portion and a signal output terminal, and a second selectable signal path connected between the output of the amplification portion and ground through a shunt device.

An apparatus comprises a plurality of selectable gain stages connected in parallel between a first bias voltage and ground, wherein each selectable gain stage comprises an amplification portion and a current steering portion, and wherein the current steering portion comprises a first selectable signal path connected between an output of the amplification portion and a signal output terminal, and a second selectable signal path connected between the output of the amplification portion and ground through a shunt device.