An amplifier (100, 300) comprising: a main amplification stage and an auxiliary amplification stage, wherein an input of the main amplification stage and an input of the auxiliary amplification stage are coupled to a common node, and an output of the main amplification stage is coupled to an output node; first switch means for selectively coupling the output node to a reference voltage (V REF); second switch means (S6, S7) for selectively coupling power from a voltage rail to the auxiliary amplification stage; third switch means (S1, S2) for selectively coupling power from the voltage rail to the main amplification stage; and a controller arranged to activate the amplifier (100, 300) by controlling the first, second and third switch means (S3, S6, S7, S1, S2), from an initial state in which the third switch means (S1, S2) de-couples the power from the main amplification stage and the first switch means couples the output node to the reference Voltage (V REF), in the following sequential order: controlling the second switch means (S6, S7) to couple the power to the auxiliary amplification stage and to establish a quiescent voltage at the common node: controlling the third switch means (S1, S2) to couple the power to the main amplification stage; and when the power is being applied to both the auxiliary amplification stage and the main amplification stage, controlling the first switch means to de-couple the output node from the reference voltage (V REF). a main amplification stage and an auxiliary amplification stage, wherein an input of the main amplification stage and an input of the auxiliary amplification stage are coupled to a common node, and an output of the main amplification stage is coupled to an output node; first switch means for selectively coupling the output node to a reference voltage (V REF); second switch means (S6, S7) for selectively coupling power from a voltage rail to the auxiliary amplification stage; third switch means (S1, S2) for selectively coupling power from the voltage rail to the main amplification stage; and a controller arranged to activate the amplifier (100, 300) by controlling the first, second and third switch means (S3, S6, S7, S1, S2), from an initial state in which the third switch means (S1, S2) de-couples the power from the main amplification stage and the first switch means couples the output node to the reference Voltage (V REF), in the following sequential order: controlling the second switch means (S6, S7) to couple the power to the auxiliary amplification stage and to establish a quiescent voltage at the common node: controlling the third switch means (S1, S2) to couple the power to the main amplification stage; and when the power is being applied to both the auxiliary amplification stage and the main amplification stage, controlling the first switch means to de-couple the output node from the reference voltage (V REF). controlling the second switch means (S6, S7) to couple the power to the auxiliary amplification stage and to establish a quiescent voltage at the common node: controlling the third switch means (S1, S2) to couple the power to the main amplification stage; and when the power is being applied to both the auxiliary amplification stage and the main amplification stage, controlling the first switch means to de-couple the output node from the reference voltage (V REF). controlling the third switch means (S1, S2) to couple the power to the main amplification stage; and when the power is being applied to both the auxiliary amplification stage and the main amplification stage, controlling the first switch means to de-couple the output node from the reference voltage (V REF).