A CMOS wide-band low-noise amplifier with balun-based noise-canceling technique

A differential high linearity low-noise amplifier (LNA) based on a capacitor-cross-coupled topology is presented in this paper. An off-chip balun is used for providing DC-bias and canceling the channel thermal noise of the transconductance MOS transistors. The LNA uses NMOS load and provides an extra signal feed-forward and noise-canceling path. Analysis shows that the noise contribution of the transconductance MOST is only gamma/20 and the noise figure (NF) of the proposed LNA is 1 + 0.2gamma. The chip is implemented in a 0.18-mum MMRF CMOS process. Measured results show that in 50 M-860 MHz frequency range, the LNA achieved 15 dB gain, 2.5 dB NF, 8.3 dBm IIP3 and consumes only 4 mA current from a 1.8-V supply.