Radio frequency low noise amplifiers

A programmable input impedance circuit for a radio frequency (RF) low noise amplifier (LNA), the programmable input impedance circuit comprising:

• a high impedance mode circuit comprising:
• an inductor-degenerated transconductor transistor;
• an inductor operatively coupled between a source of the inductor-degenerated transconductor transistor and a ground;
• a first switch operatively coupled between the inductor and the ground;
• a capacitor operatively coupled between a gate of the inductor-degenerated transconductor transistor and the source of the inductor-degenerated transconductor transistor;
• and
• a first biasing circuit operatively coupled to the source and a drain of the inductor-degenerated transconductor transistor via a second switch and a third switch, and biased to a supply voltage,
• wherein the inductor-degenerated transconductor transistor source and drain is biased to the supply voltage;
• and
• a second biasing circuit operatively coupled to the gate of the inductor-degenerated transconductor transistor via a fourth switch, and biased to ground, wherein the inductor-degenerated transconductor transistor gate is biased to ground;
• and
• a low impedance mode circuit comprising:
• a fifth switch;
• and
• a shunt resistor operatively coupled between an RF input source and alternating current (AC) ground,
• wherein the programmable input impedance circuit is configured in the low impedance mode by opening the first switch and closing the second, third, fourth, and fifth switches.

A method for configuring a radio frequency (RF) receiver comprising:

• receiving a gain requirement for an RF low noise amplifier (LNA) of the RF receiver;
• and
• selecting, based on the gain requirement, a high gain mode or a low gain mode for a programmable input impedance circuit of the RF LNA, wherein selecting the low gain mode comprises selecting a low gain mode circuit of the programmable input impedance circuit and selecting the high gain mode comprises selecting a high gain mode circuit of the programmable input impedance circuit and wherein:
• the low gain mode circuit comprising:
• a shunt resistor operatively coupled between an RF input source and alternating current (AC) ground;
• and
• the high gain mode circuit comprising:
• an inductor-degenerated transconductor transistor;
• an inductor operatively coupled between a source of the inductor-degenerated transconductor transistor and a ground;
• and
• a capacitor operatively coupled between a gate of the inductor-degenerated transconductor transistor and the source of the inductor-degenerated transconductor transistor;
• wherein receiving the gain requirement for the RF LNA of the RF receiver comprises:
• determining, by the RF receiver, that an RF input signal is at least at a threshold amount of signal integrity;
• and
• in response, selecting the low gain mode.