Title :
Optimum bias conditions for linear broadband InGaP/GaAs HBT power amplifiers
Author :
Iwamoto, M. ; Hutchinson, C.P. ; Scott, J.B. ; Low, T.S. ; Vaidyanathan, M. ; Asbeck, P.M. ; D´Avanzo, D.C.
Author_Institution :
Dept. of Electr. & Comput. Eng., California Univ., San Diego, La Jolla, CA, USA
Abstract :
A design strategy for a linear broadband InGaP/GaAs HBT power amplifier is presented. This design takes advantage of the bias dependence of the nonlinear base-collector charge, expressed by the C/sub BC/ vs V/sub CE/ and /spl tau//sub c/ vs I/sub c/ characteristics of the device. Using this technique, it is shown that the second and third order distortions have separate optimum bias conditions, and furthermore, there is an inherent tradeoff in optimizing the second and third order distortions. This strong bias dependence of the nonlinear base-collector charge and the tradeoff between the different orders of distortion are verified on a 24 dBm 0.5-11 GHz distributed power amplifier. To minimize high frequency distortion in HBT amplifiers across a wide range of bias, it is imperative to linearize the base-collector charge, where flat C/sub BC/ vs V/sub CE/ and f/sub t/ vs I/sub c/ characteristics are ideally desired.
Keywords :
III-V semiconductors; MMIC power amplifiers; bipolar MMIC; circuit optimisation; gallium arsenide; gallium compounds; harmonic distortion; heterojunction bipolar transistors; indium compounds; integrated circuit design; integrated circuit measurement; wideband amplifiers; 0.5 to 11 GHz; HBT MMIC distributed power amplifier; InGaP-GaAs; InGaP/GaAs HBT linear broadband power amplifiers; base-collector charge linearization; design strategy; device characteristics; distributed power amplifier; heterojunction bipolar transistors; high frequency distortion; nonlinear base-collector charge bias dependence; optimization tradeoff; optimum bias conditions; second order distortions; third order distortions; Bandwidth; Broadband amplifiers; Frequency; Gallium arsenide; Heterojunction bipolar transistors; Linearity; Microwave technology; Nonlinear distortion; Power amplifiers; Voltage;
Conference_Titel :
Microwave Symposium Digest, 2002 IEEE MTT-S International
Conference_Location :
Seattle, WA, USA
Print_ISBN :
0-7803-7239-5
DOI :
10.1109/MWSYM.2002.1011775