Design of a 2.5 GHz LTE 65-nm CMOS Reconfigurable Power Amplifier for UAV
Résumé
This paper presents a 2.5 GHz fully integrated Power Amplifier (PA) in 65-nm bulk CMOS TSMC process, for use in 4G LTE unmanned aerial vehicle (UAV). The proposed reconfigurable PA architecture of four sub PA cells, combined with Power Cell Switching (PCS) technique allows the high back-off output power level required by the LTE standard. The circuit presents saturated output power of +29.5 dBm, a maximum Power Added Efficiency (PAE) of 26.5 % with 6 dB of Peak to Average Power Ratio (PAPR) LTE signal at output. The four sub-PA cells are composed of three differential cascode stages, supplied by 3.3V and implemented with the segmented bias (SB) technique, reducing DC power consumption, reaching high levels of output power and reconfiguring output impedance. Two transformers have been designed to enable 100 Ohm input and output differential impedances. Another transformer is used to match the impedances between the driver and the four sub PA cells.