Gain-dependent impedance matching and linearity

An integrated circuit comprising:

• at least two input terminals configured to respectively connect to at least two band-pass filters, the at least two band-pass filters associated with different frequency band ranges;
• at least two amplifier branches, the at least two amplifier branches including:
• a first amplifier branch having a first node, a first input transistor, and a first cascode stage;
• the first input transistor having a first gate, a first source, and a first drain, the first gate connected to the at least two input terminals and the first source connected to a ground;
• the first cascode stage connected between the first drain and the first node;
• and
• a second amplifier branch having a second node, a second input transistor, and a second cascode stage;
• the second input transistor having a second gate, a second source, and a second drain, the second gate connected to the first gate and the second source connected to the ground;
• the second cascode stage connected between the second drain and the second node, the second node connected to the first node;
• and
• inductive means for providing different inductances from each of the at least two input terminals to the first gate and magnetically coupling together the first gate, the second gate, the first source, and the second source;
• the inductive means configured to produce, based on a first current that flows from the first source to the ground and a second current that flows from the second source to the ground, a portion of a third current that flows from one of the at least two input terminals towards the first gate and the second gate.

A method for gain-dependent impedance matching and linearity, the method comprising:

• generating a mutual inductance between multiple degeneration inductors, the multiple degeneration inductors respectively connected between multiple amplifier branches and a ground;
• generating another mutual inductance between an input inductor and the multiple degeneration inductors, at least a portion of the input inductor connected between the multiple amplifier branches and at least two band-pass filters, the at least two band-pass filters associated with different frequency band ranges and connected to respective input nodes of the input inductor;
• providing, via the input inductor, an inductance that is different at the respective input nodes;
• causing, based on the inductance, the mutual inductance, and the other mutual inductance, an input impedance of an amplifier to facilitate passing of a communication signal from one of the at least two band-pass filters to the amplifier, the amplifier including the multiple degeneration inductors, the multiple amplifier branches, and the input inductor;
• and
• amplifying the communication signal using one or more of the multiple amplifier branches.

An apparatus comprising:

• at least two band-pass filters having different passbands, the different passbands associated with different frequency band ranges, each band-pass filter of the at least two band-pass filters is configured to filter a received signal to produce a filtered signal;
• at least one switch module connected to the at least two band-pass filters, the at least one switch module configured to pass the filtered signal from a selected band-pass filter of the at least two band-pass filters;
• an amplifier circuit connected to the at least one switch module, the amplifier circuit including at least two amplifier branches, the amplifier circuit configured to amplify the filtered signal that is passed by the at least one switch module using one or more of the at least two amplifier branches;
• and
• multiple inductors including:
• an input inductor having an inductance, at least a portion of the input inductor connected between the at least one switch module and the amplifier circuit, the input inductor configured to provide different amounts of the inductance between each of the at least two band-pass filters and the amplifier circuit;
• and
• at least two degeneration inductors having other inductances, the at least two degeneration inductors respectively connected between the at least two amplifier branches of the amplifier circuit and a ground, the at least two degeneration inductors magnetically coupled to each other and the input inductor with respective coupling coefficients,
• the multiple inductors configured to cause an input impedance associated with the amplifier circuit and the multiple inductors to approximately equal an output impedance of the selected band-pass filter based on the respective coupling coefficients, the inductance of the input inductor, and the other inductances of the at least two degeneration inductors.