A study of phase noise in colpitts and LC-tank CMOS oscillators

Author

Andreani, Pietro ; Wang, Xiaoyan ; Vandi, Luca ; Fard, Ali

Author_Institution

Center for Phys. Electron., Tech. Univ. of Denmark, Lyngby, Denmark

Volume

40

Issue

5

fYear

2005

fDate

5/1/2005 12:00:00 AM

Firstpage

1107

Lastpage

1118

Abstract

This paper presents a study of phase noise in CMOS Colpitts and LC-tank oscillators. Closed-form symbolic formulas for the 1/f² phase-noise region are derived for both the Colpitts oscillator (either single-ended or differential) and the LC-tank oscillator, yielding highly accurate results under very general assumptions. A comparison between the differential Colpitts and the LC-tank oscillator is also carried out, which shows that the latter is capable of a 2-dB lower phase-noise figure-of-merit (FoM) when simplified oscillator designs and ideal MOS models are adopted. Several prototypes of both Colpitts and LC-tank oscillators have been implemented in a 0.35-μm CMOS process. The best performance of the LC-tank oscillators shows a phase noise of -142dBc/Hz at 3-MHz offset frequency from a 2.9-GHz carrier with a 16-mW power consumption, resulting in an excellent FoM of ∼189 dBc/Hz. For the same oscillation frequency, the FoM displayed by the differential Colpitts oscillators is ∼5 dB lower.

Keywords

1/f noise; CMOS integrated circuits; integrated circuit noise; oscillators; phase noise; 0.35 micron; 16 mW; 2.9 GHz; 3 MHz; CMOS process; Colpitts oscillators; LC-tank CMOS oscillators; MOS models; oscillation frequency; phase noise; Active noise reduction; CMOS process; Energy consumption; Noise generators; Noise level; Phase noise; Prototypes; Radio frequency; Semiconductor device modeling; Voltage-controlled oscillators; CMOS; Colpitts; LC-tank; oscillators; phase noise;

fLanguage

English

Journal_Title

Solid-State Circuits, IEEE Journal of

Publisher

ieee

ISSN

0018-9200

Type

jour

DOI

10.1109/JSSC.2005.845991

Filename

1425718