Low-noise amplifier with switched gain and method

摘要

A low noise radio frequency amplifier is switchable between a low gain state and a high gain state. A first, common-emitter transistor is active in the high gain state and inactive in the low gain state. The first transistor has a base coupled to a radio frequency input and a first bias input, an emitter coupled to ground, and a collector coupled to an amplified radio frequency output. A second, common-base transistor is active in the low gain state and inactive in the high gain state. The second transistor has an emitter coupled to the radio frequency input, a base coupled to a second bias input, and a collector coupled to the amplified radio frequency output.