A current shaping technique to lower phase noise in LC oscillators

Author

Chen, Jian ; Jonsson, Fredrik ; Olsson, Håkan ; Zheng, Li-Rong ; Zhou, Dian

Author_Institution

Electron., Comput., & Software Syst., R. Inst. of Technol., Stockholm

fYear

2008

fDate

Aug. 31 2008-Sept. 3 2008

Firstpage

392

Lastpage

395

Abstract

A novel LC-tank oscillator, where bias noise is decoupled and drain current is shaped in order to reduce phase noise, is presented. Active devices work in a class-C manner, the drain current is pulse shaped and peaks when the oscillator is insensitive to perturbations. Based on the ISF theory, this current shape can improve phase noise performance. Closed-form 1/f² phase noise equations are derived and compared with those of the classic LC-tank oscillator with the same bias and LC-tank. Simulations agree with conclusions from the theory and show 5.5 dB improvement in 1/f² phase noise at 1-MHz offset.

Keywords

1/f noise; phase noise; pulse shaping circuits; radiofrequency integrated circuits; radiofrequency oscillators; voltage-controlled oscillators; Colpitts oscillator; ISF theory; LC-tank oscillator; RF VCO; active devices; bias noise; closed-form 1/f² phase noise equations; current shaping technique; drain current; frequency 1 MHz; voltage controlled oscillator; 1f noise; Capacitors; FETs; Noise reduction; Noise shaping; Phase noise; Switches; Tail; Topology; Voltage-controlled oscillators;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronics, Circuits and Systems, 2008. ICECS 2008. 15th IEEE International Conference on

Conference_Location

St. Julien´s

Print_ISBN

978-1-4244-2181-7

Electronic_ISBN

978-1-4244-2182-4

Type

conf

DOI

10.1109/ICECS.2008.4674873

Filename

4674873