AMPLIFIER AND VOLTAGE CONTROLLED GAIN CONTROL CIRCUIT

PROBLEM TO BE SOLVED: To provide a gain control circuit provided with a large gain control amount by a small capacitor and a small inductor at the time of making an amplifier and a voltage controlled gain control circuit for the gain adjustment into a monolithic IC. SOLUTION: To an LC serial resonance circuit for constituting the gain control circuit, a transistor Q1 is serially connected. A terminal 9 among the lead terminals of a package 18 is turned to the terminal dedicated to the grounding of the gain control circuit and the ground electrode 7 of the gain control circuit on a chip and the lead terminal 9 dedicated to the grounding of the package are connected by a bonding wire 8. Since the inductance of the wire 8 and the lead terminal 9 can be utilized for the inductance of resonance, the inductance inside the chip can be small. Since only the transistor Q1 is serially connected to the serial resonance circuit and no element is parallelly connected, the Q of the resonance can be enlarged.