A High IIP2 Mixer Enhanced by a New Calibration Technique for Zero-IF Receivers

The second-order intercept point (IP2) performance of direct conversion receivers is limited by the second-order nonlinearity of the mixer. A new technique which is based on calibrating mixer by injecting a programmable nonlinear current into the mixer output is introduced in this paper. The proposed calibration technique can be used in multistandard mixers. A CMOS mixer demonstrating the performance for Universal Mobile Telecommunication System application and working with supplies as low as 1 V is designed in a 65-nm technology. The simulation results show that the mixer IIP2 is improved more than 25 dB while the mixer current consumption is increased less than 1 mA. The calibration circuit is low noise not to affect the mixer noise figure.