Switched inductor/transformer for dual-band low-noise amplifier (lna)

An apparatus comprising:

• an amplifier comprising:
• at least one first transistor configured to amplify a first signal;
• at least one second transistor configured to amplify a second signal;
• a transformer comprising a primary winding and a secondary winding;
• one or more switches configured to selectively couple the primary winding to the first transistor or the second transistor;
• a transconductance circuit coupled to the transformer, wherein:
• a first terminal of the primary winding of the transformer is coupled to a voltage rail;
• the one or more switches are configured to selectively couple a second terminal of the primary winding of the transformer to the first transistor or the second transistor;
• and
• a first terminal of the secondary winding is coupled to a first input terminal of the transconductance circuit
• a first switch configured to selectively couple the second terminal of the primary winding of the transformer to a second input terminal of the transconductance circuit;
• and
• a second switch configured to selectively couple a second terminal of the secondary winding to another voltage rail.

An apparatus comprising:

• an amplifier comprising:
• at least one first transistor configured to amplify a first signal;
• at least one second transistor configured to amplify a second signal;
• a transformer comprising a primary winding and a secondary winding;
• and
• one or more switches configured to selectively couple the primary winding to the first transistor or the second transistor;
• a transconductance circuit coupled to the transformer, wherein:
• a first terminal of the primary winding of the transformer is coupled to a voltage rail;
• the one or more switches are configured to selectively couple a second terminal of the primary winding of the transformer to the first transistor or the second transistor;
• and
• a first terminal of the secondary winding is coupled to a first input terminal of the transconductance circuit
• a first switch configured to selectively couple a first tap of the secondary winding to a second input terminal of the transconductance circuit;
• and
• a second switch configured to selectively couple a second tap of the secondary winding to a voltage rail configured to provide a common-mode voltage for the transconductance circuit.

A method for signal amplification, comprising:

• coupling at least one first transistor to a primary winding of a transformer;
• selectively coupling the primary winding of the transformer to a first input terminal of a transconductance circuit
• amplifying a first signal with the at least one first transistor;
• decoupling the at least one first transistor from the primary winding;
• coupling at least one second transistor to the primary winding of the transformer;
• selectively coupling a secondary winding of the transformer to the first input terminal of the transconductance circuit and
• amplifying a second signal with the at least one second transistor.

An apparatus for signal amplification, comprising:

• means for amplifying a first signal;
• means for amplifying a second signal;
• means for selectively coupling the means for amplifying the first signal or the means for amplifying the second signal to a primary winding of a transformer;
• means for selectively coupling the primary winding of the transformer to a first input terminal of a transconductance circuit;
• and means for selectively coupling a secondary winding of the transformer to the first input terminal of the transconductance circuit.