A New Circuit Model for Designing Fully Integrated Class-A Power Amplifier

This paper presents a new circuit model for Class-A power amplifier (PA), which can be used to guide design of fully-integrated PA by accurately estimating the optimum load resistance (Ropt), hence to achieve optimized PA performance, e.g., gain, output power (Po), power-added efficiency (PAE) and harmonics, etc. A new figure-of-merit (F) is introduced as a design criterion in practical PA design to ensure optimum overall circuit performance. This new model is verified using a two-stage fully-integrated 2.4GHz class-A PA designed and implemented in a commercial 0.35mum SiGe BiCMOS technology