A 580-$\mu$W 1.8–6 GHz Multiband Switched-Resonator SiGe VCO With 0.3-V Supply Voltage

This letter presents a fully integrated low-power low-voltage multiband switched-resonator differential cross-coupled voltage controlled oscillator (VCO) implemented in 0.18 SiGe-BiCMOS technology. The VCO operates with a supply voltage as low as 0.29 V, owing to the low knee-voltage provided by the technology, and consumes a total power of 580 muW. Utilizing a switched-resonator, the VCO covers a wide switched frequency range of 1.83-2.97 GHz and 4.36-6.17 GHz with measured phase noise of around 112.2 dBc/Hz with 0.29 V supply and 119.7 dBc/Hz with 1 V supply at 1 MHz offset. Since high-frequency bands experience higher phase noise than the low frequency bands, high- short microstrip line inductors have been used for the high-frequency bands. To the best of the authors' knowledge, the reported VCO achieves the widest switched frequency tuning range with lowest core supply voltage.