Two-Stage Band-Selectable CMOS Power Amplifiers Using Inter-Stage Frequency Tuning

JeeYoung HONG  Daisuke IMANISHI  Kenichi OKADA  Akira MATSUZAWA  

IEICE TRANSACTIONS on Electronics   Vol.E95-C   No.2   pp.290-296
Publication Date: 2012/02/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E95.C.290
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Circuits
CMOS,  power amplifier,  transformer,  

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This paper presents two CMOS power amplifiers which realize frequency band selection. Each PA consists of two stages and uses a transformer to obtain large output power with high efficiency. Furthermore, the capacitive cross-coupling at the second stage reduces a die area of the bypass capacitance. The proposed PAs are fabricated by a 0.18 µm CMOS process. With a 3.3 V supply, the PAs achieve a output 1-dB compression point of larger than 25 dBm from 2.2 GHz to 5.4 GHz, maximum of peak power added efficiency (PAEpeak) are 30% and 27% for 2-band and 3-band PAs, respectively. The proposed PAs have advantages which are a band-selectable ability within a desired frequency range and a realization of CMOS PA with high power efficiency.