Wide Band Room Temperature 0.35-dB Noise Figure LNA in 90-nm Bulk CMOS

Design and measurements of a room temperature 700 MHz - 1400 MHz low noise amplifier (LNA) in 90-nm bulk CMOS, intended for use in the Canadian large adaptive reflector (CLAR) radio telescope, are presented. The new bandwidth constrained LNA noise figure optimization and broad-banding technique as well as the importance of substrate shielding are discussed. The amplifier has 0.35 dB noise figure while consuming 45 mW of power from a 1-V supply and achieves output P1dB of -5.3 dBm and output IP3 of 7.5 dBm with the gain (S₂₁) ranging from 20.5 dB to 16.3 dB across the band. The LNA´s input and output impedances are matched to 50 Omega. The LNA represents the first CMOS design that satisfies the very demanding requirements of radio telescopes. The topology and optimization presented in this paper are not limited to radio astronomy applications and can be applied for wide band commercial applications such as tri-band GSM operating in the 850 MHz - 1900 MHz frequency range