Patent ID: 8461926

Claim:
A differential amplifier circuit comprising: a first field effect transistor including a first gate coupled to a first differential input signal terminal, a source coupled to a reference potential node, and a first drain coupled to a first differential output signal terminal; a second field effect transistor including a second gate coupled to a second differential input signal terminal, the source coupled to the reference potential node, and a second drain coupled to a second differential output signal terminal; a first variable capacitor coupled between the first gate of the first field effect transistor and the second drain of the second field effect transistor; a second variable capacitor coupled between the second gate of the second field effect transistor and the first drain of the first field effect transistor; and a first envelope detector configured to detect a first envelope of a signal at the first differential output signal terminal or the second differential output signal terminal, the first variable capacitor and/or the second variable capacitor includes a capacitance that varies in accordance with the first envelope detected by the first envelope detector.