5-GHz Band Highly Linear VCO IC with a Novel Resonant Circuit

This paper presents a 0.35-mum SiGe BiCMOS VCO IC exhibiting a linear VCO gain (K_vco) for 5-GHz band application. To realize a linear K_vco, a novel resonant circuit is proposed. The measured K_vco changes from 224 MHz/V to 341 MHz/V. The ratio of the maximum K_vco to the minimum one is 1.5 which is less than one-half of that of a conventional VCO. The VCO oscillation frequency range is from 5.45 GHz to 5.95 GHz, the tuning range is 8.8 %, and the dc current consumption is 3.4 mA at a supply voltage of 3.0 V. The measured phase noise is -116 dBc/Hz at 1MHz offset, which is similar to the conventional VCO