A 0.3–3.5?GHz active-feedback low-noise amplifier with linearization design for wideband receivers

摘要

AbstractLNAs for wideband receivers usually require a high linearity to protect the desired signals from out-band interference. Active feedback LNAs always suffer from the nonlinear feedback of source follower, and present a poor linearity. In order to solve this problem, a complementary source follower (CSF) is proposed, which utilizes the different characteristic of NMOS and PMOS to linearize the source follower, leading to an improvement of LNA’s IIP3and IIP2by about 10?dBm and 21?dBm respectively. In addition, a post-distortion technique is also used on the common source stage, which further enhances the IIP3by about 2?dBm and IIP2by 11?dBm. After using the two techniques, the noise figure (NF) does not deteriorate; instead it achieves a 0.3?dB improvement. A prototype is designed in TSMC 0.18?μm CMOS process, and a 14.8?mW power is dissipated from a 1.6?V supply. In typical process corner, across 0.3 to 3.5?GHz, this LNA achieves a 14.6?dB gain, a 2.9?dB minimum NF, and an IIP2larger than +22?dBm and IIP3larger than +1.2?dBm.]]>