一种高线性度宽带可编程增益放大器设计

Design of a high linearity wideband programmable gain amplifier

基于TSMC 0.18μm CMOS工艺,设计一款应用于软件无线电射频收发系统的高线性度宽带可编程增益放大器。采用闭环负反馈结构,通过差分运算放大器电路以及选通无源电阻电容网络实现增益dB线性可调,添加负电容电路扩展带宽,满足高线性度要求。同时,添加具有四阶巴特沃斯滤波器的直流漂移抑制电路抑制直流偏移。仿真结果表明,该可编程增益放大器在1.8V电源电压下,工作电流为7mA,增益动态范围为-11~20dB,步长为1dB,工作带宽为0~100MHz,输出1dB压缩点为14.8dBm,噪声系数为23dB。能够满足软件无线电射频收发系统的指标需求。

Based on TSMC 0.18μm CMOS process,a high linearity wideband programmable gain amplifier designed for software radio RF transceiver system is designed.The closed-loop negative feedback structure is used to achieve gain linear adjustment through the differential operational amplifier circuit and the gated passive resistor-capacitor network.A negative capacitance circuit is added to expand the bandwidth to meet the high linearity requirements.At the same time,a DC offset suppression circuit with a fourth-order Butterworth filter is added to suppress the DC offset.Post-simulation results show that with 1.8 Vpower supply voltage,the programmable gain amplifier operating current is 7 mA,the gain dynamic range is from-11 dB to 20 dB,with the step of 1 dB.The operating bandwidth is 0 ~ 100 MHz,and the output 1 dB compression point is 14.8 dBm.The noise figure is 23 dB.All these meet the standard requirement for the software-defined radio frequency transceiver systems.