Amplifier including magnetically coupled feedback loop and stacked input and output stages adapted for DC current reuse

A stacked amplifier circuit, comprising:

• an input stage including first and second input ports respectively defined by inputs of first and second transistors;
• a transformer arrangement having first and second primary windings and first and second secondary windings wherein a first end of the first secondary winding is connected to an output of the first transistor of the input stage and a first end of the second secondary winding is connected to an output of the second transistor of the input stage;
• wherein the first primary winding and the first secondary winding are arranged such that a portion of a first magnetic field generated by the first primary winding couples to the first secondary winding;
• wherein the second primary winding and the second secondary winding are arranged such that a portion of a second magnetic field generated by the second primary winding couples to the second secondary winding;
• and
• an output stage having a differential input AC coupled to the first and second secondary windings and an output connected to the first and second primary windings wherein the input stage and the output stage are arranged in a stacked configuration such that a bias current of the output stage is provided by the output stage to the input stage;
• wherein the transformer arrangement is configured to provide a signal for driving a load.