A 2.15–6.18 GHz transformer-based dual-mode LC-VCO with current-reuse technology
A dual-mode ultra-wideband VCO designed in a current-reused configuration is presented. By changing the coupling mode of the transformer tank, an ultra-wide frequency tuning range is achieved, while the current-reused topology is also incorporated to further lower the dc power consumption. Optimized in 90-nm CMOS technology, the proposed VCO attains a tuning range of 96.8% from 2.15 to 6.18 GHz, while consuming 3.8-4.5 mA of current from a 1.2 V supply. The phase noise at 1 MHz offset is from -124.7 dBc/Hz to -116.3 dBc/Hz over the entire frequency tuning range, which corresponds to a FoMT of between -201 and -204 dBc/Hz.