Abstract: A high frequency power amplifying device has two amplifying lines. Each amplifying line has a configuration in which a plurality of amplifying stages are connected in cascade having two source voltage terminals, of which one is connected to the first amplifying stage of one amplifying line and to the remaining amplifying stages of the other amplifying line, and the other, to the first amplifying stage of the latter amplifying line and to the remaining amplifying stages of the former amplifying line. An air core coil with a low D.C. resistance, formed by spirally winding a copper wire of about 0.1 mm in diameter, is connected in series between the final amplifying stage of each amplifying line and the source voltage terminal.

Abstract: An electrode on a main surface of a module board, to which an emitter electrode of a semiconductor chip formed with a switching element of a power supply control circuit that supplies a power supply voltage to amplifier circuit parts of a power module of a digital cellular phone is electrically connected to a wiring in an internal layer of the module board through a plurality of viaholes. Further, the wiring CL1 is electrically connected to an electrode for the supply of the power supply voltage, which is provided on a back surface of the module board. Accordingly, an output characteristic of the semiconductor device is improved.

Abstract: An electrode on a main surface of a module board, to which an emitter electrode of a semiconductor chip which includes a switching element of a power supply control circuit that supplies a power supply voltage to amplifier circuit parts of a power module of a digital cellular phone, is electrically connected to a wiring in an internal layer of the module board through a plurality of via holes. Further, the wiring is electrically connected to an electrode for the supply of the power supply voltage, which is provided on a back surface of the module board. Accordingly, an output characteristic of the semiconductor device is improved.

Abstract: An electrode on a main surface of a module board, to which an emitter electrode of a semiconductor chip which includes a switching element of a power supply control circuit that supplies a power supply voltage to amplifier circuit parts of a power module of a digital cellular phone, is electrically connected to a wiring in an internal layer of the module board through a plurality of via holes. Further, the wiring is electrically connected to an electrode for the supply of the power supply voltage, which is provided on a back surface of the module board. Accordingly, an output characteristic of the semiconductor device is improved.

Abstract: A high frequency power amplifying device has two amplifying lines. Each amplifying line has a configuration in which a plurality of amplifying stages are connected in cascade having two source voltage terminals, of which one is connected to the first amplifying stage of one amplifying line and to the remaining amplifying stages of the other amplifying line, and the other, to the first amplifying stage of the latter amplifying line and to the remaining amplifying stages of the former amplifying line. An air core coil with a low D.C. resistance, formed by spirally winding a copper wire of about 0.1 mm in diameter, is connected in series between the final amplifying stage of each amplifying line and the source voltage terminal. Since there is no signal leak in each amplifying line from the final amplifying stage to the first amplifying stage and the D.C. resistance of the air core coil is low, oscillation margin can be improved.