Wideband inductorless LNA employing simultaneous 2nd and 3rd order distortion cancellation

Abstract

This paper presents a wideband inductorless Low Noise Amplifier (LNA) using a technique for canceling 2nd and 3rd order intermodulation products at the same time and hence achieving high second and third order Input Intercept Point (IIP2 and IIP3) at RF and microwave frequencies. The LNA also makes use of noise canceling stage to achieve low noise characteristics and low noise figure in the whole bandwidth. The LNA was designed in 90-nm CMOS process and consists of a shunt feedback common-source input stage to provide wideband input impedance matching, followed by a noise canceling stage. The common source input stage employs two transistors in parallel biased at different operating regions which perform distortion cancellation. IIP2 and IIP3 of the designed LNA are +41dBm and +2.4dBm respectively. The LNA achieved the voltage gain of 17dB while having the noise figure below 2dB from 500MHz–5GHz.