0.18μm CMOS Power Amplifier For 5.25GHz Wireless LAN Systems

The growing popularity of Internet demands high data rate wireless local area network(WLAN).Using the unlicensed national information infrastructure(UNII) band,WLAN systemscan provide data rates up to several tens of megabits per second.The radio frequency(RF)integrated circuit is the design bottleneck of the WLAN systems.The IC technology for RF circuits continues to change. Performance, cost and time to market are three critical factors influencing the choice of technologies in the competitive RF industry.Supported by the enormous momentum of the digital market,CMOS devices have achieved high transit frequencies.In the resent years,RF CMOS has suddenly become the topic of active research.This paper presents the design of a 5.25GHz CMOS power amplifier based on TSMC 0.18μm RFCMOS technology for IEEE802.11a WLAN systems.Simulation results and layout are provided.There we used two stages of differential structure and cascode structure,also we present a class of operation (parallel A&B) using two transistor in parallel at the output stage for efficiency and linearity enhancement.With a supply voltage of 3.3V,its gain is 24.7dB,Pout,1dB=23.7dBm,the maximum PAE (Power Added Efficiency)is 34.4%.It can be expected to used in IEEE802.11a WLAN systems.Firstly,architectures and specifications of the RF transmitter are discussed.And the category of WLAN has been given.Secondly,the circuits and specifications of all kinds of power amplifiers are focused.Then,it introduces the details of the design from five aspects,including cells dividing,analysis of stability,and design of matching network,design of bias network and design of main amplifiers.The simulation results have also as been presented.Finally,the realization of the layout of the power amplifier is given.