Patent ID: 7026858

Claim:
A switch semiconductor integrated circuit having a switch FET for controlling passage of a high-frequency signal so that the switch FET is switched between on-operation and off-operation by a switching signal applied to a gate of the switch FET, wherein the switch semiconductor integrated circuit includes a logic control section using an inverter circuit which generates the switching signal in accordance with a control signal applied from outside, the inverter circuit uses a junction-type FET to which a resistance load connected to a power source is connected, and the gate of the switch FET is connected to an output end of the inverter circuit via a gate resistor, and the output end is connected to a coupling capacitor which couples a part of the high-frequency signal, the coupling capacitor being connected between one of the drain and source of the switch FET and the output end of the inverter circuit, wherein the gate resistor is connected between the gate of the switch FET and one end of the coupling capacitor, whereby the coupled high-frequency signal is rectified by an equivalent diode between the gate and drain of the junction-type FET, and is superposed onto a DC voltage applied to the gate of the switch FET.