Ultra low power 5.4-GHz current-reused VCO with internal LC series resonance in 0.18-µm CMOS technology

A novel circuit topology suitable for the implementation of CMOS voltage-controlled-oscillator (VCO) fabricated in TSMC 0.18-μm has been presented in this paper. While current-reused structure can save dc power consumption dynamically, and measured dc power consumption at 1.2 V is about 0.9 mW. The measurement results exhibit a frequency tuning range of 140 MHz in the vicinity of 5.4 GHz. For high output level, we utilize the cascode structure to increase output swing and excite output power to -2.06 dBm at buffer. The measured phase noise at 1 MHz and DC current are -112.7 dBc/Hz and 0.75 mA, respectively. The result evaluated by means of a figure of merit is about -188 dBc/Hz.