2-V, 1-GHz CMOS inductorless LNAs with 2-3 dB NF

Two 1 GHz single-stage single-ended low noise amplifiers (LNAs), requiring one external inductor and matched to 50 /spl Omega/ at both the input and output, have been designed using a 0.5 /spl mu/m CMOS technology. Both LNAs employ a cascode topology with a resistive pull-up load and with no on-chip inductor. The second topology uses an AC-coupled active-inductor load to provide more selectivity and reject the image channel. The LNAs have a gain greater than 10 dB at 1 GHz with a noise figure lower than 3 dB at a power dissipation of 17 mW from a 2 V supply. The inductor-less LNA has an IIP3 of -3.8 dBm compared to the active-inductor LNAs IIP3 of -21 dBm and their reverse isolation is higher than 45 dB.