Title :
A first RF digitally-controlled oscillator for SAW-less TX in cellular systems
Author :
Hung, Chih-Ming ; Barton, Nathen ; Staszewski, Robert B. ; Lee, Meng-Chang ; Leipold, Dirk
Author_Institution :
Wireless Analog Technol. Center, Texas Instrum. Inc., Dallas, TX, USA
Abstract :
A first digitally-controlled oscillator for mobile stations is presented. Combining a MTM capacitor and two NMOS transistor arrays for the varactor as an RF DAC, a highly linear oscillator gain is achieved, and is insensitive to process shift. With a sigma-delta dithering, a fine frequency resolution is obtained while having negligible phase noise degradation. The measured -167dBc/Hz at 20MHz offset from 915MHz carrier proves that this DCO system can be used in a SAWless transmitter for mobile phones.
Keywords :
cellular radio; mobile radio; phase noise; radio transmitters; radiofrequency integrated circuits; radiofrequency oscillators; sigma-delta modulation; varactors; voltage-controlled oscillators; 20 MHz; 915 MHz; MTM capacitor; NMOS transistor arrays; RF DAC; RF digitally-controlled oscillator; SAWless transmitter; cellular systems; digital-analog converter; gate oxide reliability; highly linear oscillator gain; mobile phones; mobile stations; phase noise degradation; process shift; quantization noise; sigma delta modulation; sigma-delta dithering; varactor; voltage controlled oscillator; Capacitors; Degradation; Delta-sigma modulation; Gain; MOSFETs; Oscillators; Phase noise; Radio frequency; Transmitters; Varactors;
Conference_Titel :
VLSI Circuits, 2005. Digest of Technical Papers. 2005 Symposium on
Print_ISBN :
4-900784-01-X
DOI :
10.1109/VLSIC.2005.1469414
