Effect of resistive feedback on performance parameters of common source LNA

Abstract

Effect of resistive feedback on performance parameters of Common-Source (CS) low noise amplifier (LNA) is studied in this paper. For this purpose, an ultra low power, low noise figure (NF), high power gain (S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</inf> ) low noise amplifier (LNA) for narrowband (NB) wireless applications is proposed in this paper. The LNA is designed for 2.4 GHz narrowband (NB) using 90nm CMOS process. It has a 3-dB bandwidth of 2.189–2.637 GHz. It consists of a resistive feedback Common-Source (CS) inductive degeneration main stage followed by Common-Gate (CG) cascoded stage. A series inter-stage inductor between the main stage and the cascoded stage is used to achieve the low NF with desired stability and power gain. The proposed LNA achieves power gain (S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</inf> ) of 23.4 dB, input return loss (S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1I</inf> ) of −2.4 dB, output return loss (S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</inf> ) of −27 dB and reverse isolation (S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</inf> ) less than −34.67 dB. The proposed LNA circuit provides acceptable values of input 1-dB compression (P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> dB) and input third-order intercept point (IIP3) as −32.8 dBm and IIP3 −18.5 dBm respectively. The LNA has NF < 3.21 dB and consumes only 1.44 mW under a power supply of 0.8 V.