Low noise amplifier (LNA) suitable for large dynamic range operation

摘要

An amplifier having multiple gain modes comprises a plurality of cascoded input transistors arranged in parallel, a degeneration stage connected to the input transistors and having a variable impedance, and switching means for switching between different gain modes of the amplifier by switching off one or more of the input transistors and varying the impedance of the degeneration stage. The invention provides an LNA architecture which preserves input impedance match across a large dynamic range.