Design Of Ultra-low CMOS Mixer

With the rapid development of integrated circuit technology and wireless communications equipment, low-voltage and low-power analog integrated circuit design becomes a popular technology gradually. Particularly, the crossing course of these two fields- RF integrated circuit technology has become a hot in this issue. The performance of mixer, as a very important part of receiver, directly affects the performance of the entire communication equipment.In this paper, the receivers, such as the super heterodyne receivers, zero-IF receivers and low-IF receivers were introduced. The functions of all kinds of receivers were analyzed and compared. The structure of mixers, the principle of work and the main performance parameter were introduced in detail. On the basis of Gilbert double-balanced CMOS-mixer, an ultra-low voltage mixer is proposed using the bulk-driven technique .Using Hspice simulator and BSIM3V3 models for CSMC 0.5μm CMOS process, the mixer was simulated. The simulation result shows that the mixer can work properly at 300MHz frequency with a single power supply of 1V. The conversion gain of this mixer is -14.7dB, and the Third-order Input Intercept Point is 32.6dB. The low-voltage mixer based on Quasi-Floating Gate Transistors was also simulated. The result shows its validity.