A selectable bandwidth LNA based on current conveyors

Abstract

A selectable bandwidth CMOS Low Noise Amplifier (LNA) implemented in UMC 90nm process is presented. The LNA employs two current conveyors as building blocks to implement a wideband UHF (470 MHz to 862 MHz) voltage amplifier. By means of a switch and an LC tank added at the output, the LNA can operate also in the GSM narrowband (1.8 GHz). Using this simple technique it is possible to use only one LNA for both standards. Simulation results validate the proposed circuit. The simulated power gain (S21) is 13 dB for UHF band, and 6 dB for GSM. The input return loss (S11) is better than -10 dB in both modes. The amplifier has a simulated noise figure (NF) of 5.8 dB for UHF band and 6.3 dB when it is working in GSM band. This amplifier draws 3.9 mA from a ±1.2V supply.