Design of common-base differential low noise amplifier

In the wireless communication terminals,the low noise amplifier is the first level of active circuits in RF system,which has an important impact on the performance of system.After analyzing the noise in-depth,this paper afforded the low-noise amplifier with common-base differential input structure.The circuit included the controlled gain amplifier and gain control circuit.The output voltage of low-noise amplifier was directly connected to the input of AGC circuit.According to the output voltage amplitude,the AGC circuit output voltage was fed to the comparator input of the low noise amplifier gain control circuit,affecting the overall gain of amplifier.The circuit is designed and simulated based on the JAZZ 0.35 μm BICMOS process.The results show that the amplifier can effectively suppress the noise,low-noise amplifier can provide 25 dB gain,noise parameter is less than 1dB,and the sensitivity reaches 2μV.