A noise-suppressed amplifier with a signal-nulled feedback for wideband applications

This paper presents a noise suppression technique that is based on the feedback topology for wideband low-noise amplifiers. By nulling the signal in the noise feedback loop, the noise suppression and the signal performance like gain, input matching and output linearity can be considered independently. The overhead on power dissipation is small since the extra loop has less linearity concern. To demonstrate its feasibility, a shunt-feedback type LNA with the proposed noise suppression loop is implemented in a 0.18 mum CMOS process. The signal bandwidth is 1.3 GHz. The voltage gain and noise figure are 14.1 dB and 4.8 dB respectively. The current consumption is 1.18 mA from a 1.3 V supply voltage.