Abstract: A bias circuit and a low-noise amplifier circuit including the same provided. The bias circuit may be connected to a first transistor configured to amplify an input radio frequency (RF) signal and may be configured to provide a bias voltage to a second transistor that amplifies an output RF signal of the first transistor. The bias circuit may include a current source configured to receive a power supply voltage and generate a reference current, and a current-to-voltage conversion circuit configured to convert the reference current into the bias voltage and provide the bias voltage to a control terminal of the second transistor.

Abstract: A low noise amplifier is provided. The low noise amplifier includes a first transistor that receives a radio frequency (RF) signal through a control terminal, a second transistor that forms a cascode structure together with the first transistor, and receives an output signal of the first transistor through a first terminal, and a third transistor that forms a cascode structure together with the second transistor, and receives an output signal of the second transistor through the first terminal. The first to third transistors perform an amplification operation in response to application of a first power source voltage, and the first and second transistors or the first and third transistors perform an amplification operation in response to application of a second power source voltage.