Automatic frequency shift compensation (AFSC) in resonant tank circuits over the process variation

A method for operating a low noise amplifier, the method comprises:

• providing a first input signal to a first output circuit, to a first input port of an automatic frequency shift compensation circuit and to a first port of an inductor;
• providing a second input signal to a second output circuit, to a second input port of the automatic frequency shift compensation circuit, and to a second port of the inductor;
• biasing the inductor via a third port, by a bias circuit;
• amplifying the first input signal by the first output circuit to provide a first output signal;
• and
• amplifying the second input signal by the first output circuit to provide a second output signal;
• wherein the automatic frequency shift compensation circuit comprises a first capacitor, a second capacitor, a first variable capacitor, a second variable capacitor and a tuning circuit;
• wherein the first input port is electrically coupled to a first end of the second variable capacitor, to a first end of the first capacitor, to an input of the first output circuit, and to a first port of the inductor;
• wherein the second input port is electrically coupled to a second end of the first variable capacitor, to a second end of the second capacitor, to an input of the second output circuit, and to a second port of the inductor;
• wherein a first port of the first varactor is electrically coupled to a second end of the first capacitor;
• wherein a second port of the second varactor is electrically coupled to a first end of the second capacitor;
• and
• wherein the method further comprises controlling, by the tuning circuit, a capacitance of the first varactor and a capacitance of the variable capacitor.