A unified description of multiple feedback common-gate low-noise amplifiers (LNAs) is presented, providing analytical expressions for gain, noise figure, linearity, and stability conditions. Moreover, from the theory, a new methodology for LNA optimization is developed. This new approach, called adaptive optimization, uses the ability to reconfigure the feedback network to match the amplifier characteristics to the changing working conditions. Results of simulation of LNAs with different feedback types are shown, and they confirm the theory presented.