Analysis and design of a 1.0-V CMOS mixer based on variable load technique

Abstract

A CMOS active mixer based on variable load technique which can operate at 1.0V supply voltage is proposed and its operation principle, noise and linearity analysis are presented. Different from the conventional Gilbert mixer based on RF current-commutating, the proposed mixer controls the load impedance according to the LO signal. It has only two stacked transistors at each branch which is suitable for low-voltage applications. The mixer was fabricated in 0.18-μm 1P6M CMOS process and measured in 2.4-GHz ISM band. With an input 2.440GHz RF signal and a 2.442GHz LO signal, the conversion gain is 5.3dB, the input-referred third-order intercept points is 4.6dBm, the input-referred 1dB compression point is −7.4dBm, and the single-sideband noise figure is 21.7dB. Total DC current consumption is 3.5mA.