Radio-frequency integrated circuit for a radio-frequency wireless transmitter-receiver with reduced influence by radio-frequency power leakage

Abstract

In an RF front end portion for processing a radio-frequency signal in a portable telephone, a low pass filter allowing passing of only a signal in a frequency band lower than a radio-frequency signal component band is arranged between a circuit processing a high power signal and a control circuit controlling operation of the radio-frequency signal processing circuit. The radio-frequency signal processing circuit is a transmission/reception multiplexing circuit transferring a transmission signal of the portable telephone to an antenna or receiving a reception signal from the antenna, and the control circuit is a transmission/reception control circuit determining an operation mode of the transmission/reception multiplexing switch. Alternatively, the radio-frequency signal processing circuit includes a power amplifier amplifying a signal to be transmitted, and a gate voltage control circuit generating gate bias voltage controlling a gain of the power amplifier. The influence of a radio-frequency leakage component leaking from a gate of the field effect transistor can be suppressed. In the case of the transmission/reception multiplexing switch, handing power can be improved, and an increase in power consumption and occupied area of the control circuit can be suppressed. In the case of the power amplifier, the gate bias voltage can be held stably, and the power amplification can be performed accurately. In the portable telephone, the RF front end portion processing the radio-frequency signal can be provided in a chip occupying a small area.