Wide Tuning Range 4-Stage Ring VCO for Phase Locked Loop

A new four stage differential ring voltage-controlled oscillator (VCO) is introduced in this paper for wide tuning-range applications of phase-locked loops (PLLs). A differential delay cell equipped with a CMOS inverter-based frequency tuning mechanism is proposed to widen the tuning frequency range of the ring oscillator. 90nm CMOS technology(GPDK90) is utilized to simulate the proposed oscillator. The supply voltage selected for this design is 1.0V. The built-in oscillator achieves a tuning frequency range of 2.07 GHz to 7.56 GHz, and this range is obtained by increasing the control voltage from 0.0V to 0.5V. The proposed oscillator can produce 526µW of power at its maximum. The mentioned oscillator attained a power efficiency value of 0.06mW/GHz. At 1 MHz offset, the proposed oscillator exhibits -86.28dBc/Hz phase noise, and the obtained value of Figure of Merit (FOM) is -166.64 dBc/Hz.