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A CMOS Envelope Tracking Power Amplifier for LTE Mobile Applications
함정현,정해련,김형철,임원섭,허득현,양영구 대한전자공학회 2014 Journal of semiconductor technology and science Vol.14 No.2
This paper presents an envelope tracking power amplifier using a standard CMOS process for the 3GPP long-term evolution transmitters. An efficiency of the CMOS power amplifier for the modulated signals can be improved using a highly efficient and wideband CMOS bias modulator. The CMOS PA is based on a two-stage differential common-source structure for high gain and large voltage swing. The bias modulator is based on a hybrid buck converter which consists of a linear stage and a switching stage. The dynamic load condition according to the envelope signal level is taken into account for the bias modulator design. By applying the bias modulator to the power amplifier, an overall efficiency of 41.7 % was achieved at an output power of 24 dBm using the 16-QAM uplink LTE signal. It is 5.3 % points higher than that of the power amplifier alone at the same output power and linearity.
양극 크기에 따른 0.18㎛ SiGe PIN 다이오드 특성
정동호(Dong-Ho Jeong),권정혁(Jung-Hyuk Kwon),허득현(Deuk-Hyoun Heo) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.7
This paper analyzed series resistance and surface recombination properties by SiGe PIN diodes (anode area=6.25㎛² , 50㎛², and 400㎛²) with a unique octagonal geometry based on a standard 0.18 ㎛ SiCMOS technology. The bulk minority carrier lifetime extracted from the 1/τe vs perimeter to area itar (P/A) plot is approximately 6.2 ㎳ at cutoff condition which is very small. In addition, they reveal low series resistance and small surface recombination velocity for good RF switch application.