A Load-Shared CMOS Power Amplifier With Efficiency Boosting at Low Power Mode for Polar Transmitters

• Published in: IEEE transactions on microwave theory and techniques Vol. 56; no. 7; pp. 1565 - 1574
• Main Authors: Dong Ho Lee, Changkun Park, Jeonghu Han, Younsuk Kim, Songcheol Hong, Chang-Ho Lee, Laskar, J.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.07.2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amplifiers; Applied sciences; Boosting; Cascode amplifiers; Circuit analysis; Circuit properties; CMOS; CMOS technology; CMOSFET power amplifiers (PAs); Design. Technologies. Operation analysis. Testing; Differential amplifiers; Drains; Driver circuits; Electric potential; Electric, optical and optoelectronic circuits; Electronic circuits; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; Integrated circuits; Load; Low voltage; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwaves; mode locking; monolithic microwave integrated circuit (MMIC) PAs; polar transmitters; Power amplifiers; Power generation; RLC circuits; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transmitters; Voltage; Performance evaluation; MOSFET; Load distribution; Output power; Differential amplifier; Microwave transmitter; mode locking; Driver; Power supply; Self bias; Implementation; Low voltage; Complementary MOS technology; polar transmitters; Learning algorithm; CMOSFET power amplifiers (PAs); Gate voltage; Class E; Resonant circuit; Cascode amplifiers; monolithic microwave integrated circuit (MMIC) PAs; Power electronics; Cascode connection; Resource sharing; Complementary MOS transistor; Power amplifier; Low-power electronics
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2008.925220

A load-shared CMOS power amplifier (PA) for 1.8-GHz polar transmitter applications has been implemented in standard 0.18-mum CMOS technology and fully characterized to demonstrate its efficiency boosting technique in low power mode. With the aid of cascode amplifiers, the load-shared configuration achieves efficiency improvement at low supply voltage in a polar transmitter. A differential class-E amplifier with a parallel resonant circuit is analyzed and incorporated in the load-shared PA. The load-shared configuration is composed of driver amplifiers (DAs) and PAs whose output loads are shared. The DA has a constant gate voltage biasing of a cascode amplifier for efficiency boosting, whereas the PA has a self-biased cascode configuration to be turned on and off by a supply voltage. The measurement results of the load-shared configuration show a drain efficiency increase from 6% to 30% at 16-dBm output power compared with a conventional self-biased cascode amplifier. The load-shared PA is reported with 35.6% of power-added efficiency and 32.2 dBm of output power at 1.88 GHz.