A New Linearization Technique for CMOS Low Noise Amplifiers with Balun Circuitry

In this paper, a new linearization technique for differential low noise amplifiers (LNAs) is introduced. It removes the common-mode current at all frequencies. One of itsmain advantages is that it allows the receiver to have a singleended input and a differential output LNA which attenuateseven-order inter-modulations. Also, this technique improves theLNA linearity in three ways. Firstly, it removes the commonmode current of all inter-modulations. Secondly, it attenuateseven-order inter-modulations because of its balun circuitry operation. Finally, it improves the third input intercept point(IIP3) due to the possibility of different bias currents for input transistors. Simulation results using a 0.18μm RF-CMOS technology with HSPICE-RF show that the IIP3 improves about 13 dBm at the expense of increasing the noise figure about 0.7 dB in constant voltage gain and equal DC-power respected to the conventional differential LNA

Keywords:

LNA , inter-modulation , IM2 , IM3 , IIP2 , IIP3 , transconductance