A 2.4-GHz Temperature-Compensated CMOS LC-VCO for Low Frequency Drift Low-Power Direct-Modulation GFSK Transmitters

Toru TANZAWA  Kenichi AGAWA  Hiroyuki SHIBAYAMA  Ryota TERAUCHI  Katsumi HISANO  Hiroki ISHIKURO  Shouhei KOUSAI  Hiroyuki KOBAYASHI  Hideaki MAJIMA  Toru TAKAYAMA  Masayuki KOIZUMI  Fumitoshi HATORI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E88-C   No.4   pp.490-495
Publication Date: 2005/04/01
Online ISSN: 
DOI: 10.1093/ietele/e88-c.4.490
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Low-Power LSI and Low-Power IP)
Category: Analog
Keyword: 
GFSK,  CMOS LC-VCO,  Bluetooth,  direct modulation,  low power,  

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Summary: 
A frequency drift of open-loop PLL is an issue for the direct-modulation applications such as Bluetooth transceiver. The drift mainly comes from a temperature variation of VCO during the transmission operation. In this paper, we propose the optimum location of the VCO, considering the temperature gradient through the whole-chip thermal analysis. Moreover, a novel temperature-compensated VCO, employing a new biasing scheme, is proposed. The combination of these two techniques enables the power reduction of the transmitter by 33% without sacrificing the performance.