Title :
Low-power 2.4GHz CMOS frequency synthesizer with differentially controlled MOS varactors
Author :
Shin, Sangho ; Lee, Kwyro ; Kang, Sung-Mo
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., KAIST, Daejeon
Abstract :
A fully-differential quadrature PLL with common-mode noise immunity has been developed by using a differentially controlled quadrature-VCO (Q-VCO) along with a differential charge-pump (CP). To increase the common-mode rejection ratio (CMRR) of Q-VCO, a simple bias shifting technique was used with accumulation-depletion mode MOS varactors. The measured minimum CMRR of the Q-VCO control gain is more than 30dB and the frequency tuning range is 26.3% around the 2.5GHz center frequency with a 3-bit capacitor bank array. To reduce the overall power consumption, an architectural optimization and an inter-stage impedance matching (ISM) techniques were used in frequency divider circuits. Our frequency synthesizer was fabricated in a 1P6M 0.18mum RFCMOS process, and the measured phase noise is -112dBc/Hz at 1MHz offset from the 2.458GHz output frequency while the total PLL current consumption is 8.2mA for 1.8V supply voltage
Keywords :
CMOS integrated circuits; MIS devices; UHF integrated circuits; frequency dividers; frequency synthesizers; impedance matching; low-power electronics; phase locked loops; phase noise; varactors; voltage-controlled oscillators; 0.18 micron; 1.8 V; 2.4 GHz; 3 bit; 8.2 mA; CMOS frequency synthesizer; CMRR; ISM techniques; Q-VCO; RFCMOS process; accumulation-depletion mode MOS varactors; architectural optimization; bias shifting technique; capacitor bank array; common-mode noise immunity; common-mode rejection ratio; differential charge-pump; differentially controlled MOS varactors; differentially controlled quadrature-VCO; frequency divider circuits; inter-stage impedance matching techniques; phase noise; quadrature PLL; Charge pumps; Circuit optimization; Energy consumption; Frequency measurement; Frequency synthesizers; Gain measurement; MOS capacitors; Phase locked loops; Tuning; Varactors;
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.2006.1692645
