一种适用于WiMAX/LTE发射机的高线性、可变带宽、可变增益滤波器设计

摘要

This paper describes a highly linear, programmable bandwidth, programmable gain, fourth order Butterworth low pass filter for WiMAX/LTE transmitters with a O.Bum RF CMOS process. This filter has seven programmable bandwidths which from 2.1MHz tol2MHz; 30dB programmable gain range with ldB per step and gain step error less than 0.05dB; the third harmonic distortion less than -65dB at 1.5MHz output signal with 4dBm output power when the filter's bandwidth is 12MHz. The circuit area is 0.45mm2. The supply voltage is 1.2V. The circuit consumes 12mW at the largest bandwidth and 4mW at the least bandwidth. The LPF has been successfully applied to direct-conversion WiMAX/LTE transmitters.%采用0.13μm RF CMOS工艺,实现了一个高线性、带宽可变、增益可调的四阶巴特沃兹低通滤波器.此滤波器带宽2.1～12MHz,7种带宽控制,30dB增益范围,1dB增益步进,增益步进误差小于0.05dB,在最大带宽下,输出信号频率1.5MHz,功率4dBm时的三阶谐波失真小于-65dB.芯片面积为0.45mm2.电源电压1.2V,在最大带宽下功耗为12mW,最小带宽下功耗为4mw.此低通滤波器已经成功地应用在WiMAX/LTE直接变频发射机中.