Analysis of different feedback topologies to LNA input matching

This paper describes the analysis of different feedback topologies to LNA input matching. The effect of different components to LNA input impedance is discussed. Analyzed feedback topologies can also be used to eliminate the source inductor found in IDCS LNA and feedback can be used to achieve matching in packaged LNA where the bond wire is no longer a free design parameter. A design example, using a 1.2-V 65-nm CMOS process, is given for a packaged LNA to demonstrate that adequate performance can be achieved using the presented theory and topologies.