A UWB CMOS low-noise amplifier with noise reduction and linearity improvement techniques
In this paper, a highly linear CMOS low noise amplifier (LNA) for ultra-wideband applications is presented. The proposed LNA improves both input second- and third-order intercept points (IIP2 and IIP3) by canceling the common-mode part of all intermodulation components from the output current. The proposed LNA structure creates equal common-mode currents with the opposite sign by cascading two differential pairs with a cross-connected output. These currents eliminate each other at the output and improve the linearity. Also, the proposed LNA improves the noise performance by canceling the thermal noise of the input and auxiliary transistors at the output. Detailed analysis is provided to show the effectiveness of the proposed LNA structure. Post-layout circuit level simulation results using a 90nm RF CMOS process with Spectre-RF reveal 9.5dB power gain, -3dB bandwidth (BW?3dB) of 8GHz from 2.4GHz to 10.4GHz, and mean IIP3 and IIP2 of +13.1dBm and +42.8dBm, respectively. The simulated S11 is less than ?11dB in whole frequency range while the LNA consumes 14.8mW from a single 1.2V power supply.
linearity common-mode current ultra-wideband cmos lna noise figure intermodulation distortion cancellation noise cancellation