A Multi-Band CMOS LC Quadrature VCO for GSM/DCS/DECT/WCDMA/Bluetooth Systems

In this work, a multi-band CMOS Voltage Control Oscillator (VCO) using the LC tank technique is developed to meet phase noise requirements of GSM, DCS, DECT, WCDMA(CDMA2000) and Bluetooth. To accomplish the multi-band receiving architecture at a low hardware cost, the proposed VCO based on switched capacitors and cross-coupled transistors without tail transistors is designed to yield quadrature output signals. Our Quadrature VCO (QVCO) fabricated by the TSMC 0.18um 1P6M CMOS technology is operated at 1V with a die size of 0.95mm
²
. At 600-kHz offset, the phase noises of the proposed QVCO are -124dBc/Hz, -122dBc/Hz, -125dBc/Hz, -118dBc/Hz and -124dBc/Hz at 0.9GHz, 1.8GHz, 1.9GHz, 2.2GHz and 2.4GHz, respectively. Therefore, the proposed QVCO is demonstrated to have sufficiently good performance for these standard applications.