Low-Power and Low-Phase-Noise $G_{m}$ -Enhanced Current-Reuse Differential Colpitts VCO

A Colpitts voltage-controlled oscillator (VCO) is presented for low-power and low-phase-noise applications. The current efficiency of the proposed VCO is improved through ${g} _{{m}}$ -enhanced and current-reuse techniques. In addition, a clover-shaped inductor is employed to mitigate electromagnetic interference (EMI) effects. The VCO is implemented in a 0.18- ${ \mu }\text{m}$ CMOS process and is shown to operate at frequencies of 2.34 to 2.55 GHz with a tuning range of 8.6%. The prototype has a power dissipation of 1.4 mW and achieves a phase noise of −122.85 dBc/Hz at a 1 MHz frequency offset.