Title :
A technique to suppress tail current flicker noise in CMOS LC VCOs
Author :
Saeedi, S. ; Mehrmanesh, S. ; Tajalli, A. ; Atarodi, M.
Author_Institution :
Microelectron. Res. & Dev. Center of Iran
Abstract :
A technique to reduce close-in phase noise in CMOS LC voltage controlled oscillators is proposed. In CMOS differential LC oscillators, the up-conversion of flicker noise mainly determines the close-in phase noise. The flicker noise of the bias current is a major component contributing to the overall low frequency noise. In this paper, a switched biasing technique to suppress the flicker noise of the bias circuit is presented. A 1.8V 2.4GHz differential LC VCO is designed in a 0.18mum CMOS technology using this technique. With the proposed switching technique, the close in phase noise is improved as much as 15dB at 500 kHz offset. The simulated phase noise at the offsets of 500 kHz and 1 MHz is -124.6dBc/Hz and -130.3dBc/Hz, respectively. The VCO consumes 2mA from a 1.8v power supply
Keywords :
CMOS integrated circuits; UHF integrated circuits; UHF oscillators; circuit noise; flicker noise; interference suppression; phase noise; voltage-controlled oscillators; 0.18 micron; 1.8 V; 2 mA; 2.4 GHz; CMOS LC VCO; CMOS LC voltage controlled oscillators; CMOS differential LC oscillators; CMOS technology; bias circuit; close-in phase noise; switched biasing technique; tail current flicker noise suppression; 1f noise; CMOS technology; Circuit noise; Frequency; Low-frequency noise; MOSFETs; Noise reduction; Phase noise; Tail; Voltage-controlled oscillators;
Conference_Titel :
Circuits and Systems, 2006. ISCAS 2006. Proceedings. 2006 IEEE International Symposium on
Conference_Location :
Island of Kos
Print_ISBN :
0-7803-9389-9
DOI :
10.1109/ISCAS.2006.1693313
