Title :
High efficiency CDMA RF power amplifier using dynamic envelope tracking technique
Author :
Staudinger, J. ; Gilsdorf, B. ; Newman, D. ; Norris, G. ; Sadowniczak, G. ; Sherman, R. ; Quach, T.
Author_Institution :
Semicond Products Sector, Motorola Inc., Tempe, AZ, USA
Abstract :
This work describes a 2-W peak-envelope linear power amplifier based upon the envelope tracking (ET) technique with application to CDMA cellular radio handsets. Both drain voltages of a two stage monolithic GaAs IC are varied with respect to the long term rms value of the modulated signal using a high efficiency Class-S modulator. The modulator is implemented as a single chip silicon IC to supply currents in excess of 1 A. The RF amplifier IC utilizes two AlGaAs/InGaAs heterostructure insulated-gate FET structures which allows single voltage supply operation with state-of-the-art linearity and efficiency performance. When driven by a CDMA O-QPSK signal, the ET amplifier exhibits desired spectral linearity while achieving a remarkable 5/spl times/ improvement in overall efficiency, compared to fixed supply bias, when measured in a reverse link urban based mobile transmitter power profile.
Keywords :
cellular radio; code division multiple access; power amplifiers; radiofrequency amplifiers; telephone sets; 2 W; AlGaAs-InGaAs; AlGaAs/InGaAs heterostructure insulated gate FET; CDMA cellular radio handset; GaAs; GaAs IC; O-QPSK signal; RF power amplifier; Si; class-S modulator; efficiency; envelope tracking; linearity; reverse link urban mobile transmitter; silicon IC; FET integrated circuits; High power amplifiers; Insulation life; Linearity; Multiaccess communication; Power amplifiers; Radio frequency; Radiofrequency amplifiers; Radiofrequency integrated circuits; Voltage;
Conference_Titel :
Microwave Symposium Digest. 2000 IEEE MTT-S International
Conference_Location :
Boston, MA, USA
Print_ISBN :
0-7803-5687-X
DOI :
10.1109/MWSYM.2000.863319
