WIDEBAND POWER AMPLIFYING CIRCUIT, CONCERNED WITH FILTERING/AMPLIFYING VARIOUS RANGES OF FREQUENCY BAND SIGNALS AND PREVENTING CONFUSION OF OUTER SIGNALS

摘要

PURPOSE: A wideband power amplifying circuit is provided to couple an LC filter with a PA(Power Amplifier) used for amplifying a signal in a communication terminal, thereby filtering/amplifying various ranges of frequency band signals and preventing confusion of outer signals. CONSTITUTION: A transistor(Tr) amplifies a signal transceived from a terminal. The first capacitance(C1) cuts off a DC component of a signal inputted to a base terminal of the transistor(Tr). A resistor(R) controls a feedback gain of the amplified signal. The second capacitance(C2) is connected to a contact where the first capacitance(C1) is coupled with the resistor(R) in serial, and functions as a band pass filter. The second capacitance(C2) determines a low frequency component.