Low noise amplifier with single-ended input, double-ended output and adjustable gain

The invention discloses a low noise amplifier with single-ended input, double-ended output and adjustable gain and belongs to the field of wireless communication circuits. The low noise amplifier comprises a single-ended to differential amplifier circuit (100) and buffer circuits (200), wherein the single-ended to differential amplifier circuit (100) comprises a differential magnification adjusting sub-circuit (100); the low noise amplifier further comprises a grid amplifier tube (Mg) connected to a single-ended input end (In1) and a source amplifier tube (Ms) connected to the grid amplifier tube (Mg); the source amplifier tube (Ms) comprises a plurality of NMOS (N-channel Metal Oxide Semiconductor) units; the different numbers of NMOS units are selectively connected to adjust the dimension multiple of the source amplifier tube (Ms) relative to the grid amplifier tube (Mg), so that the differential magnification of a single-ended input signal (SIn) is adjusted to obtain differential signals of different magni