A low power 2.4-GHz current reuse VCO for low power miniaturized transceiver system

The explosive growth of short range wireless communication systems has lead to highly demand of compact radio frequency (RF) circuit with low power design. As voltage control oscillator (VCO) is the core block of RF systems, this paper presents a low power and highly miniaturized current reuse 2.45 GHz VCO. The proposed VCO is designed with the staking switch two series transistors using current reuse topology and inversion-mode of PMOS varactor tank. The proposed VCO consists a single on chip inductor and four MOS transistors that simplifies the VCO circuit and shrink the chip area remarkably. The proposed VCO is designed with 0.18-μm CMOS process. At 1.2 V DC supply, the proposed VCO draws only 315 μA current resulted to the VCO operate at ultra low power (0.38 mW). Over the tuning range the proposed VCO has the phase noise of -127 dBc/Hz at 1 MHz offset. In order to eliminate additional matching voltage circuit, the tuning voltage (Vtune) is kept similar to the DC voltage supply for 2.45 GHz ISM band applications. The performance of the proposed VCO show the excellent optimization for low power of compact transceiver system.