Semiconductor integrated circuit with variable gain amplifier

A semiconductor integrated circuit comprising:

• a matching circuit;
• and
• a variable gain resistive feedback amplifier including a transistor for amplification, a load resistance, a voltage follower for feedback, and a feedback resistance,
• wherein the matching circuit is supplied with an RF input signal received by an antenna of a receiver of a wireless system,
• wherein a common terminal of an emitter or a source of the transistor for amplification is connected to a predetermined reference voltage,
• wherein an output signal of the matching circuit is supplied to an input terminal of a base or a gate of the transistor for amplification,
• wherein the load resistance is connected between an output terminal of a collector or a drain of the transistor for amplification and a power supply voltage,
• wherein the output terminal of the transistor for amplification is connected to an input of the voltage follower for feedback,
• wherein the feedback resistance is connected between an output of the voltage follower for feedback and the input terminal of the transistor for amplification,
• wherein, in the variable gain resistive feedback amplifier, resistance values of the load resistance and feedback resistance are changed in response to a gain control signal in cooperation,
• wherein, when the load resistance is controlled to a high load resistance in response to the gain control signal setting the variable gain resistive feedback amplifier to a high gain, the feedback resistance is controlled to a high feedback resistance, and
• wherein, when the load resistance is controlled to a low load resistance, lower than the high load resistance, in response to the gain control signal setting the variable gain resistive feedback amplifier to a low gain, the feedback resistance is controlled to a low feedback resistance that is lower than the high feedback resistance.