Self-calibrating gain control circuit for low noise amplifier

摘要

An amplifier comprises a Low Noise Amplifier (LNA) that amplifies a Radio Frequency (RF) signal that includes a transconductance, a gain and an input stage that receives the RF signal. A bias assembly includes a bias circuit with a bias resistance and generates a bias current for the input stage of the LNA, which is related to the bias resistance. A shunt feedback stage amplifies an output of the input stage, generates an RF output and includes a shunt resistance. Changes in the bias resistance due to changes in conditions are substantially offset by changes in the shunt resistance due to the changes in conditions, which reduces variation of the gain of the LNA based on the changes in conditions.