Patent ID: 7317356

Claim:
A low-noise amplifier circuit, comprising: an amplifier having a positive input, a negative input, a positive output, a negative output, and an open-loop gain A o ; a first transistor providing a first parasitic capacitance at the positive input and a second transistor providing a second parasitic capacitance at the negative input; a third transistor coupled between the positive output and the positive input and providing thereby a first feedback capacitance comprising the parasitic capacitance of said third transistor; a fourth transistor coupled between the negative output and the negative input and providing thereby a second feedback capacitance comprising the parasitic capacitance of said fourth transistor, wherein the first feedback capacitance has a value that is a predetermined percentage of the first parasitic capacitance and the second feedback capacitance has a value that is a predetermined percentage of the second parasitic capacitance, and a first shorting switch coupled to the positive input and adapted to selectively short the positive input to ground and a second shorting switch coupled to the negative input and adapted to selectively short the negative input to ground, wherein when such switches short the respective inputs to ground, the amplifier's zero bias operating condition is established and wherein when such switches are open, no direct current path exists between the respective inputs and ground.