LNA with variable gain and switched degeneration inductor

An amplifier including:

• (a) a plurality of amplifier branches;
• (b) a plurality of branch control switches, each branch control switch coupled to a corresponding amplifier branch;
• (c) a degeneration module including:
• (1) a degeneration inductor having at least one tap;
• and
• (2) at least one degeneration switch having a first terminal coupled to a corresponding one of the taps and a second terminal coupled to ground;
• wherein the degeneration inductor is formed within an area of having a defined shape and the at least one degeneration switch is formed outside the area.

An amplifier including:

• (a) a plurality of amplifier branches;
• (b) a plurality of branch control switches, each branch control switch coupled to a corresponding amplifier branch;
• (c) a degeneration module including:
• (1) a degeneration inductor having at least one tap;
• and
• (2) at least one degeneration switch having a first terminal coupled to a corresponding one of the taps and a second terminal coupled to ground;
• wherein the number of amplifier branches is equal to the number of branch control switches.

An amplifier including:

• (a) a plurality of amplifier branches;
• (b) a plurality of branch control switches, each branch control switch coupled to a corresponding amplifier branch;
• (c) a degeneration module including:
• (1) a degeneration inductor having at least one tap;
• and
• (2) at least one degeneration switch having a first terminal coupled to a corresponding one of the taps and a second terminal coupled to ground;
• further comprising a plurality of selectable degeneration capacitors coupled to the source of the common source amplifier.

A method for amplifying comprising:

• (a) applying an input signal to a plurality of amplifier branches;
• (b) turning on each of the amplifier branches by means of a plurality of branch control switches, each branch control switch coupled to a corresponding amplifier branch;
• and
• (c) selecting the inductance of a degeneration inductor having at least one tap by means of at least one degeneration switch having a first terminal coupled to a corresponding one of the taps and a second terminal coupled to ground;
• wherein the degeneration switches have a control input and wherein the amplifier further includes a gain control module having at least one switch control output, each switch control output coupled to the control input of a corresponding one of the degeneration switches.