Patent ID: 8314658

Claim:
A power amplifier comprising: a plurality of primary inductors arranged as a whole in a circular geometry over a semiconductor substrate; and a plurality of amplifier pairs provided corresponding to the primary inductors on the semiconductor substrate, respectively, each amplifier pair including first and second amplifiers coupled, respectively, to two ends of a corresponding primary inductor, each of said first and second amplifiers having an input node coupled, respectively, to a common first input terminal and a common second input terminal, and amplifying and outputting to the corresponding primary inductor each of a pair of first and second signals given as differential input signals, a secondary inductor provided adjacent to the primary inductors over the semiconductor substrate and arranged in a circular geometry with one turn or multiple turns and, by being magnetically coupled to the primary inductors, further combining and outputting signals made by combining the first and second signals at each of the primary inductors; and a connection wiring provided inside the primary inductors over the semiconductor substrate and electrically coupling middle points of the primary inductors with each other, wherein each of the middle points is a point over the primary inductor and also a point at the same distances from two ends of the primary inductor and wherein said plurality of primary inductors and said connection wiring are formed using same wiring layer.