A varactor configuration minimizing the amplitude-to-phase noise conversion in VCOs

Author

Bonfanti, Andrea ; Levantino, Salvatore ; Samori, Carlo ; Lacaita, Andrea L.

Author_Institution

Dipt. di Elettronica e Informazione, Politecnico di Milano, Milan

Volume

53

Issue

3

fYear

2006

fDate

3/1/2006 12:00:00 AM

Firstpage

481

Lastpage

488

Abstract

Amplitude-to-phase-noise conversion due to varactors can severely limit the close-in phase noise performance in LC-tuned oscillators. This work proposes a rigorous analysis of this phenomenon, which highlights the fundamental limitations of single-ended tuned and differentially tuned diode varactor configurations. The back-to-back varactor topology is identified as a suitable solution to linearize the tank capacitance. The amplitude to phase noise conversion is greatly attenuated and the 1/f³ phase noise is drastically reduced, without impairing the achievable tuning range. These results are validated through circuit simulations in an existing 0.35-mum CMOS technology

Keywords

1/f noise; CMOS integrated circuits; integrated circuit noise; phase noise; varactors; voltage-controlled oscillators; 0.35 micron; 1/f phase noise; CMOS technology; LC-tuned oscillators; amplitude-to-phase noise conversion; circuit simulations; diode varactor configurations; phase noise performance; tank capacitance; varactor topology; voltage controlled oscillator; CMOS technology; Capacitance; Circuit optimization; Circuit topology; Diodes; Noise level; Oscillators; Phase noise; Tuning; Varactors; Diode varactor; flicker noise up-conversion; phase noise; voltage controlled oscillator;

fLanguage

English

Journal_Title

Circuits and Systems I: Regular Papers, IEEE Transactions on

Publisher

ieee

ISSN

1549-8328

Type

jour

DOI

10.1109/TCSI.2005.858764

Filename

1610847