Wide band LNA with BW expansion by capacitive feed forward technique

Abstract

This paper presents wide band low noise amplifier (LNA) that utilizes shunt feedback topology (SF). SF based lna suffers from strict trade-off between the input matching reflection coefficient (S'il) and noise figure NF. To break this trade-off feed forward (FF) stage is added to achieve two in-phase nodes in the path of the signal where a negative Miller capacitance can be obtained by employing another capacitive FF resulting in partial cancellation of the parasitic capacitance associated with the dominant pole hence expanding the BW of both gain and S'il while slightly affect the NF. The LNA was realized using 90 nm CMOS technology and achieves gain of 14 dB, Su < −10 dB and NF less than 2.2 dB in the frequency range from 0.5–2.2 GHz and less than 2.8 dB in the entire BW of 0.1–5GHz while draws 10 mA from 1.2 V DC source and occupies 0.003 mm2