HIGH-FREQUENCY POWER AMPLIFYING CIRCUIT

摘要

A high-frequency power amplifyi9ng circuit enabling suppression of the amount of variation of the collector current at the final stage even if the impedance of the load varies. The high-frequency power amplifying circuit comprises a final-stage transistor (Tr2) having a collector terminal (TC2) connected to an output terminal (102) through a capacitor (C3) and an output matching circuit (202) and a preceding-stage transistor (Tr1) having a collector terminal (TC1) connected to the base terminal (TB2) of the transistor (Tr2) through a capacitor (C2). The base terminal (TB1) of the transistor (Tr1) is connected to an input terminal (101) through a capacitor (C1) and the input matching circuit (201). Between the base terminal (TB2) and a base bias voltage applying terminal (110), resistors (R11, R13) are connected in series in order from the base bias voltage applying terminal (110) side. Between the connection node between the resistors (R11, R13) and the base terminal (TB1), a resistor (R12) is connected.