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第 26 卷第 10 期半导体学报 Vol. 26 No. 10
2005 年 10 月 CHIN ESE J OURNAL OF SEMICONDUCTORS Oct. ,2005
A 2 4 GHz Quadrature Output Frequency Synthesizer
Yi Xiaofeng , Fang Han , Yang Yujia , and Hong Zhiliang
( S tate Key L aboratory of A S IC and S ystem , Fudan Universit y , S hanghai 200433 , China)
Abstract : A design and implementation for a 2 4 GHz quadrature output frequency synthesizer intended for blue
tooth in 0 35μm CMOS technology are presented. A differentially controlled quadrature voltage controlled oscillator
(QVCO) is employed to generate quadrature ( I/ Q) signals. A second order loop filter ,wνith a unit gain transconduct
ance amplifier having the performance of a third order loop filter ,is exploited for low cost. The measured spot phase
noise is - 106 15dBc/ Hz ***@1M Hz. Close in phase noise is less than - 70dBc/ Hz. The synthesizer consumes 13 5mA
under a 3 3V voltage supply. The core size is 1 3mm × 0 8mm.
Key words : frequency synthesizer ; phase locked loop ; quadrature VCO ; phase noise ; bluetooth
: 1205 ; 1230 ; 1285
CLC number : TN742 Document code : A Article ID : 0253 4177 (2005) 10 1910 06
out design. Moreover ,no gain can be obtained since
1 Introduction t he filter is passive. Another problem is t hat t he
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