A black-box approach to RF LNA design

This paper presents a novel power-constrained algorithmic design methodology for radiofrequency (RF) low-noise amplifiers (LNAs). The methodology is based on matrix descriptions of the transistors allowing for the first time the derivation of exact synthesis equations for input impedance matching and transducer gain optimization. The equations are embedded in an algorithm for design tradeoffs between noise performance and gain. In particular, the synthesis equations are demonstrated for the cascode topology with inductive degeneration. The matrices required by the mathematical description are derived through simulations, allowing the algorithmic design methodology to be accurate, flexible (i.e. applicable to any two-port active device), and compliant with the needs of intellectual property protection since no dc, small-signal, or noise model parameters are required. The methodology is validated through the design of a 2 mW 2.45 GHz LNA in a predictive 90 nm CMOS technology.