Double feedback technique for reduction of Noise LNA with gain enhancement

In this paper we present a balun low noise amplifier (LNA) in which the gain is boosted by using a double feedback structure. The circuit is based on a conventional balun LNA with noise and distortion cancelation. The LNA is based on the combination of a common-gate (CG) stage and common-source (CS) stage. We propose to replace the load resistors by active loads, which can be used to implement local feedback loops (in the CG and CS stages). This will boost the gain and reduce the noise figure (NF). Simulation results, with a 130nm CMOS technology, show that the gain is 24dB and the NF is less than 2.7dB. The total power dissipation is only 5.4mW (since no extra blocks are required), leading to a figure-of-merit (FOM) of 3.8mW-1 using a nominal 1.2V supply. Measurement results are presented for the proposed DFBLNA included in a receiver frontend for biomedical applications (ISM and WMTS)