宽带高增益输出平衡CMOS低噪声放大器的设计

设计了一种带片内变压器、适用于0.05～2.5 GHz频段的宽带低噪声放大器(LNA).电路设计采用了并行的共栅共源放大结构,将从天线接收到的单端输入信号转换为一对差分信号输出给后级链路.针对变压器结构的LNA噪声系数不够低和输出不平衡的问题,采用了缩放技术、噪声消除技术以及两级的全差分放大器作为输出缓冲级,来有效降低电路的噪声系数,提高增益和输出平衡度.电路采用TSMC 0.18μm 1P6M RF CMOS工艺设计仿真和流片,测试结果表明:在0.05 ～ 2.5 GHz频带范围内,该LNA的最高功率增益达24.5 dB,全频段内噪声系数为2.6～4 dB,输入反射系数小于-10 dB,输出差分信号幅度和相位差分别低于0.6dB和1.8°.

Design of a Wideband CMOS Low Noise Amplifier with High Gain and Output Balance

A wideband low noise amplifier (LNA) with integrated balun for 0.05-2.5 GHz frequency band was designed.The circuit was designed based on the paralleled cascade amplification structure which converted the single-ended input signal received from the antenna into a pair of differential signals for output to the post link.Aiming at the problem that the noise figure of the LNA with balun structure was not low enough and its output was unbalanced,the scaling technology,noise elimination technology and the two-stage fully differential output buffer were adopted to effectively reduce the noise figure of the circuit and improve the gain and output balance.The circuit was designed,simulated and fabricated with the TSMC 0.18 μm 1P6M RF CMOS process.The test results show that within the bandwidth of 0.05-2.5 GHz,the LNA achieves a maximum power gain of 24.5 dB,a noise figure of 2.6-4 dB in the whole frequency band,an input reflection coefficient of less than-10 dB,and an output differential signal amplitude and phase difference of less than 0.6 dB and 1.8°,respectively.