一种低功耗双模式有源RC复数滤波器

A Low Power Dual-Mode Active RCComplex Filter

基于g_m/I_D设计方法和电流复用型折叠共源共栅运算放大器结构,采用SMIC 0.18μm CMOS工艺,设计了一种应用于卫星接收机的低功耗可自动调谐双模式有源RC复数滤波器。引入了调零电阻,补偿由非理想运算放大器引起的Q值升高导致的通带纹波性能恶化。同时,引入了全集成调谐电路模块,补偿无源器件在IC制造中因工艺偏差导致的频率响应偏移。仿真结果表明:滤波器分别工作在GPS-L1和BD-B1模式,中心频率为4.092 MHz(带宽2 MHz)和6 MHz(带宽4MHz)时,镜像抑制比分别为65dB和61dB,增益分别为2dB和-1dB。滤波器芯片面积为0.6mm^2,在1.8V电源电压下,功耗仅为1.75mW。

Based on gm/IDdesign method and current recycling folded cascode op-amp structure,a low power dual-mode active RCcomplex filter with automatic frequency tuning circuits for navigation receiver was designed in the SMIC 0.18μm process.The nulling resistor was introduced to compensate the effects of passband ripple deterioration caused by Qincrease because of non-ideal op-amp.At the same time,a fully integrated tuning circuit module was employed to compensate the frequency response offset resulting from the process deviation of passive components in IC manufacturing process.The simulation results showed that the image rejection ratio（IRR）was nearly 65 dB and 61 dB,the DC gain was 2 dB and-1 dB respectively when the complex filter worked at GPS-L1/BD-1 mode,which centered at 4.092 MHz（with 2 MHz bandwidth）/6 MHz（with 4 MHz bandwidth）.The chip occupied an area of 0.6 mm^2.Attractively,the filter only consumed 1.75 mW at a power supply of 1.8 V.