A Three-Mode Switched-LNA Using a Low Parasitic Capacitance MOSFET Switch

Toshifumi NAKATANI  Koichi OGAWA  Junji ITOH  Ikuo IMANISHI  

IEICE TRANSACTIONS on Electronics   Vol.E86-C   No.6   pp.1032-1040
Publication Date: 2003/06/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Devices and Circuits for Next Generation Multi-Media Communication Systems)
low noise amplifier,  noise figure,  MOSFET switch,  parasitic capacitance,  3rd-order intercept point,  dissipation power,  cross-modulation,  

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A three-mode switched-LNA has been developed using a 0.25 µm SiGe BiCMOS technology. The LNA features low noise figure (NF) performance, while achieving both low dissipation power and low distortion characteristics. The proposed MOSFET switch incorporating a newly developed switch circuit with a triple-well structure, which changes the LNA's mode, provides a parasitic capacitance of just 0.52 times that of a conventional MOSFET switch. This results in a significant NF improvement, by 0.16-0.33 dB, for the three-mode switched-LNA compared to a conventional LNA. Extensive studies of the MOSFET switch with regard to the structural parameters and the doping profiles are reported. Experimental results and the overall performance of a trial IC incorporating the three-mode switched-LNA are also given.