A merged up-conversion mixer-VCO based on current reuse

This paper presents a novel merged circuit which can be used in wireless transmitter. This circuit joins up-conversion mixer and voltage controlled oscillator (VCO) together. The block plays an important role in a transmitter. The design is single-end input and output which can be applied to a communication system with 50ohm antenna directly. The proposed design adopts current reuse and matching work reuse structures. This solution can reduce the use of passive devices efficiently, so as to reduce the area of chip. The circuit is designed with SMIC 0.18um RF CMOS technology. Simulation results shown that, under a 1.2V voltage supply, the DC power consumption of the whole circuit is only about 4.7mW, the max conversion gain is 7.8dB, the noise figure is less than 20dB with a frequency range from 880MHz to 920MHz, and the phase noise is lower than -124dBc/Hz with 1MHz offset the 900MHz center frequency.