Methods, systems, and apparatus, including computer programs encoded on computer storage media, for radio frequency (RF) low noise amplifier (LNA) circuit configured to receive an input RF signal from an RF input source and provide an amplified output RF signal, where the RF LNA circuit includes an amplifier circuit, where the amplifier circuit is configured to receive the input RF signal and provide the amplified output RF signal, and an inductor-degenerated transconductor input impedance circuit that is separate from the amplifier circuit and that is operatively coupled to the input of the amplifier circuit.