Amplifier with switchable common gate gain buffer

摘要

An amplifier having a switchable common gate gain buffer is disclosed. In an exemplary embodiment, an apparatus includes a plurality of selectable gain channels that provide constant input impedance at a common input to receive an input signal and generate an output signal having at least one of selected gain and current characteristics. At least two gain channels utilize transistors having different transconductance values. The apparatus also includes at least one impedance network coupled to at least one gain channel to provide the constant input impedance.

主权项

1. An apparatus comprising:
a low-noise amplifier configured to amplify an input signal to produce a buffer input signal in response to a selected gain; a gain buffer having an input coupled to an output of the low-noise amplifier, the gain buffer comprising a plurality of selectable gain channels that provide constant input impedance at a common input to receive the buffer input signal and generate an output signal having at least one of selected gain and current characteristics, wherein at least two gain channels utilize transistors having a common-gate configuration and having different transconductance values, the gain buffer configured to produce the output signal in response to the buffer input signal and a gain of a selected gain channel; and at least one impedance network coupled to at least one gain channel to provide the constant input impedance.