An amplifier includes a first coil coupled to at least one input node. The amplifier further includes second and third coils. A first terminal of the second coil is coupled to a source terminal of a first transistor, while a second terminal of the second coil is coupled to a source terminal of a second transistor. A third coil includes first and second terminals coupled to gate terminals of the first and second transistors, respectively. Responsive to receiving an input signal, the first coil electromagnetically conveys the signal to the second and third coils.

An amplifier includes a first coil coupled to at least one input node. The amplifier further includes second and third coils. A first terminal of the second coil is coupled to a source terminal of a first transistor, while a second terminal of the second coil is coupled to a source terminal of a second transistor. A third coil includes first and second terminals coupled to gate terminals of the first and second transistors, respectively. Responsive to receiving an input signal, the first coil electromagnetically conveys the signal to the second and third coils.

An apparatus includes a differential amplifier. The differential amplifier includes a first side circuit configured to receive a first input signal, a second side circuit configured to receive a second input signal, and a resonant tank circuit coupled between the first and second side circuits. A first capacitor and first switch may be provided in series between a source and drain of a cascode transistor. A second capacitor and second switch may be provided in series between a source and drain of an input transistor. A method includes receiving a first input signal by a first side circuit, receiving a second input signal by a second side circuit, controlling a resource of a resonant tank circuit, and outputting an output signal according to the first and second input signals. The resource of the resonant tank circuit may be controlled according to a transmission mode, frequency band, or both.