An 11.2-mW 5-GHz CMOS Frequency Synthesizer with Low Power Prescaler for Zigbee Application

Xincun JI  Fuqing HUANG  Jianhui WU  Longxing SHI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E94-C   No.3   pp.375-378
Publication Date: 2011/03/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E94.C.375
Print ISSN: 0916-8516
Type of Manuscript: BRIEF PAPER
Category: Electronic Circuits
Keyword: 
CMOS,  WSN,  half-integer phase-switching prescaler,  frequency synthesizer,  

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Summary: 
A 1.8 V, 5 GHz low power frequency synthesizer for Wireless Sensor Networks is presented in 0.18 µm CMOS technology. A low power phase-switching prescaler is designed, and the current mode phase rotator is merged into the first divide-by-2 circuit of the prescaler to reduce power and propagation delay. An improved charge pump circuit is proposed to compensate for the dynamic effects with the charge pump. By a divide-by-2 circuit, the frequency synthesizer can provide a 2.324-2.714 GHz quadrature output frequency in 1 MHz steps with a 4 MHz reference frequency. The measured output phase noise is -110 dBc/Hz at 1-MHz offset frequency. The power consumption of the PLL is 11.2 mW at 1.8 V supply voltage.