| 摘要 |
PROBLEM TO BE SOLVED: To obtain a power amplifier capable of increasing flexibility in design by reducing a bottom operational voltage and reducing input/output impedance mismatches in an attenuation mode. SOLUTION: An amplifying transistor Tr for amplifying an RF signal is provided between an input terminal and an output terminal. A cathode of a diode Da1 is connected to the input terminal, and an anode of a diode Da2 is connected to the output terminal. A matching and attenuating circuit MA is connected between an anode of the diode Da1 and a cathode of the diode Da2. The matching and attenuating circuit MA reduces impedance mismatches between an input terminal side and an output terminal side and attenuates the RF signal. During an amplification mode, a bias circuit B2 supplies a bias current to the amplifying transistor Tr and a current mirror circuit CM turns off the diodes Da1, Da2. During an attenuation mode, the bias circuit B2 does not supply the bias current to the amplifying transistor Tr and the current mirror circuit CM turns on the diodes Da1, Da2. COPYRIGHT: (C)2009,JPO&INPIT
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