Title :
Theory and design of an ultra-linear square-law approximated LDMOS power amplifier in class-AB operation
Author :
Van der Heijden, Mark P. ; De Graaff, Henk C. ; De Vreede, Leo C N ; Gajadharsing, John R. ; Burghartz, Joachim N.
Author_Institution :
Dept. of Inf. Technol. & Syst., Delft Univ. of Technol., Netherlands
fDate :
9/1/2002 12:00:00 AM
Abstract :
This paper describes a power amplifier, employing parallel-connected laterally diffused metal-oxide semiconductor (LDMOS) devices with optimized channel widths and bias offsets to approximate ideal square-law behavior of the overall transconductance in class-AB operation. The proposed method results in a significant linearity improvement over a large dynamic range in comparison to a conventional amplifier in class-A or class-AB operation. Measurements demonstrate an improvement of 20 dB in third-order intermodulation distortion and 10 dB in adjacent channel power ratio for wide-band code-division multiple access at 12-dB output power backoff from the 1-dB gain compression point. Consequently, this amplifier can be operated more toward the compression region with better linearity and drain efficiency compared to a conventional LDMOS power-amplifier design
Keywords :
MOSFET circuits; code division multiple access; intermodulation distortion; power amplifiers; radiofrequency amplifiers; LDMOS RF power amplifier; adjacent channel power ratio; class-AB operation; drain efficiency; dynamic range; linearity; third-order intermodulation distortion; transconductance; ultra-linear square-law approximation; wideband code division multiple access; Broadband amplifiers; Distortion measurement; Dynamic range; Linearity; MOS devices; Operational amplifiers; Power amplifiers; Power measurement; Semiconductor optical amplifiers; Transconductance;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2002.802332
