A 4 dBm IP1dB 20.8 dBm UP3 wideband complementary SF feedback LNTA with derivative superposition method

摘要

A wideband low-noise transconductance amplifier (LNTA) with high linearity is proposed for SAW-less applications. Complementary source-follower and common-source stage are adopted to solve the second-order nonlinear feedback problem. Derivative superposition (DS) method is employed to decrease the second- and third-order nonlinearity of the main path. Moreover, large-signal input matching performance is preserved due to the push-pull operation. Designed in a 0.18-μm CMOS process, the simulation results show that it provides a minimum noise figure (NF) of 2.4 dB, and a maximum trans-conductance of 81 mS from 0.17 to 3.17 GHz. An input 1-dB compression/desensitization point of 4.14/1.58 dBm and an IIP3 of 20.8 dBm are obtained, respectively. The input matching performance is maintained even with a 6 dBm blocker, and the blocker NF is 3.1 dB under a 0 dBm blocker. The circuit draws 9.1 mA from a 1.8 V supply and the core area is only 0.068 mm2.