A low-phase-noise wide-band CMOS quadrature VCO for multi-standard RF front-ends
This work develops a broadband quadrature voltage-controlled oscillator (QVCO) for digital video broadcasting (DVB) tuner applications. The QVCO is mainly based on a balanced voltage-controlled oscillator (VCO), which is a combination of two single-ended VCO. Two active ports and two resonant tanks balance the phase of outputs and also increase the operating range. Experimental results show that the proposed broadband QVCO achieves a 1.1 ~ 2.4 GHz wide tuning range with a 74 % fractional bandwidth. The phase noise and quadrature-phase error are respectively lower than -109 dBc/Hz at 100 kHz offset frequency and 5 degrees over the 1.3 GHz operating bandwidth. Index Terms – Voltage-controlled oscillator, local oscillator, low noise, DVB, broadband radio.