Wideband Inductor-less LNA with Resistive Feedback and Noise Cancelation

Abstract

In this master thesis a wideband, inductorless LNA for GSM and WCDMA with noise canceling is examined and designed in 90-nm RF CMOS process. The goal was to design a wideband LNA that could work as a drop in solution in ST-Ericsson’s receiver and have an input match below -12 dB for a bandwidth of 800 MHz to 2.5 GHz. The proposed LNA combines two techniques, resistive feedback and noise cancellation to provide both a wideband input match and good noise and linearity performance. The result is a wideband, differential LNA without any need for external matching components. Furthermore, the solution is inductorless which saves valuable area on chip. The LNA covers frequency bands within 800 MHz – 2.5 GHz with S11 below -12.8 dBm and provides a voltage gain of 27 dB. The NF is below 2.1 dB and IIP3 is greater than -4 dBm with a power consumption of only 28 mW. In the receiver test bench the mixer is used as load which results in a conversion gain higher than 24 dB, S11 below -12.8 dBm, NF below 4 dB and IIP3 higher than -6.2 dB. This solution has many features such as high bandwidth with a good input match, inductorless design saving area and costs and is fully differential.