Low-noise amplifier with tuned input and output impedances

An amplifier comprising:

• a first capacitor, a first terminal of the first capacitor coupled to receive a single-ended input signal;
• a first transistor, a control terminal of the first transistor being coupled to a second terminal of the first capacitor, and a first current terminal of the first transistor being coupled to a first constant reference potential;
• a first resistor coupled between the control terminal of the first transistor and the first constant reference potential;
• a second transistor, a control terminal of the second transistor being coupled to a second current terminal of the first transistor, and a first current terminal of the second transistor being coupled to the control terminal of the first transistor;
• and
• a frequency-selective network coupled between the second current terminal of the first transistor and a second current terminal of the second transistor,
• wherein the amplifier generates, in differential form, an amplified output signal representing the single-ended input signal across a first terminal of the frequency selective network and a second terminal of the frequency selective network.

A device comprising:

• an antenna to receive an input signal via a wireless medium;
• a low-noise amplifier (LNA) to amplify the input signal and to generate an amplified signal;
• a down-converter to lower the carrier frequency of the amplified signal and to generate a down-converted signal;
• an analog to digital converter (ADC) to generate digital values representing the down-converted signal;
• and
• a baseband processor to process the digital values,
• wherein the LNA comprises:
• an input terminal to receive the input signal;
• a pair of output terminals to provide the amplified signal in differential form;
• a first transistor coupled between a first one of the pair of output terminals and a constant reference potential, wherein a control terminal of the first transistor is coupled to the input terminal, the first transistor to amplify the input signal;
• a second transistor coupled between a second one of the pair of output terminals and the input terminal, wherein a control terminal of the second transistor is coupled to the first one of the pair of output terminals;
• and
• a frequency-selective network coupled between the first one of the pair of output terminals and the second one of the pair of output terminals.