A 1.3~2.2 GHz Low Phase-Noise Low-Power CMOS LC VCO

This paper presents a wide-band low phase-noise and low power voltage-controlled oscillator (VCO). To cover a frequency range of 1.3~2.2 GHz and maintain extremely low gain, a bunch of 128 tuning curves realized by 7-bit switching capacitor array is applied in VCO. On the other hand, wide-range leads to huge gain variation. To combat it, a 3-bit self-controlled varactor array is also proposed. Besides, to enlarge each tuning curve linear range, distributed biased varactor technique is still adopted. Fabricated in TSMC 0.18 μm CMOS process, the tuning curve linear range is 0.2~1.6 V, and VCO can cover 1.3~2.17 GHz frequency. The overlap of high band adjacent curves is more than 50%, and low band is even more than 80%. The average gain is only 19 MHz/V, and the fluctuation range is 13~25 MHz/V. For 1312 MHz, the VCO phase noise is -116.53dBc/Hz at 1MHz offset; while for 2 152 MHz, it is -112.78 dBc/Hz. VCO consumes 1.2~3.2 mA for a 1.8 V supply voltage. The proposed VCO can achieve wide tuning range and low phase noise. It has been successfully integrated in the frequency synthesizer for Wireless networks for Industrial Automation (WIA) applications.