Patent ID: 7312482

Claim:
A power amplifier device having one or a plurality of amplification systems, wherein said amplification system has a semiconductor chip in which a transistor is formed and a plurality of external electrode terminals, wherein said external electrode terminals are an input terminal to which a signal to be amplified is supplied, an output terminal for outputting the amplified signal, and first, second, and third power source terminals, wherein said transistor is electrically connected between said input terminal and said output terminal, wherein electrodes of said transistor are a control electrode connected to said input terminal and said third power source terminal, a first electrode connected to said output terminal and said first power source terminal, and a second electrode connected to said second power source terminal serving as an earth terminal, wherein a first plurality of electrode pads, corresponding to said input, output, first power source and third power source terminals, are formed over a top face of said semiconductor chip, wherein said first plurality of electrode pads are electrically connected, via conductive wires, to said corresponding input, output, first power source and third power source terminals, wherein a second plurality of electrode pads are formed on a portion of said second electrode of said transistor, wherein said second plurality of electrode pads are electrically connected via conductive wires to said second power source terminal, wherein each of said electrodes of said transistor is constructed by a base portion and a plurality of fingers projected in a direction orthogonal to said base portion, one of the fingers of said first electrode is disposed between two neighboring fingers of said second electrode, wherein said second electrode is connected to a fixed potential, and wherein each of said fingers of said second electrode, which are positioned at opposite ends of the base portion of said second electrode, has a first width, and wherein each of said fingers of said second electrode, which are positioned between said fingers at the opposite ends, has a second width, and wherein the first width is wider than the second width.