This paper describes a dual-looped PLL architecture to improve voltage-to-frequency linearity of VCO. The V-I converter employing a current-pumping algorithm is proposed to enhance the linearity of the VCO circuit. The designed VCO operates at a wide frequency range of 75.8 MHz-1 GHz with a good linearity. The PFD circuit design technique preventing fluctuation of the charge pump circuit under the locked condition is discussed. Simulation results show that a locking time of the proposed PLL is 3.5 µs at 1 GHz and the power dissipation is 92 mW.