一种带有精准调谐结构的有源RC低通滤波器的设计

提出了一种带有精准调谐结构的有源RC低通滤波器的设计方案,其截止频率为5MHz,并在0.18μm标准CMOS工艺线上流片得到验证.调谐精度达到(-1.24%,+2.16%),测试中得到验证.调谐系统所占芯片面积仅为主滤波器面积的1/4.调谐系统完成调谐功能后会自动关闭,降低了功耗以及对主滤波器的串扰.以50Ω作为源阻抗,滤波器带内3阶交调量(IIP3)好于16.1dBm.滤波器输入参考噪声为36μVrms.滤波器群延迟时间波动测试结果为24ns.滤波器功耗为3.6mW.带有这种调谐结构的滤波器容易被实现,可以用于很多无线低中频应用中,例如全球定位系统、全球通和码分多址等芯片系统中.

Design of an Active-RC Low-Pass Filter with Accurate Tuning Architecture

An active-RC low-pass filter of 5MHz cutoff frequency with a tuning architecture is proposed. It is implemented in 0. 18μm standard CMOS technology. The accuracy of the tuning system is improved to be within (-1.24%, + 2. 16%)in measurement. The chip area of the tuning system is only a quarter of that of the main-filter. After tuning is completed,the tuning system will be turned off automatically to save power and to avoid interference. The in-band 3rd order harmonie input intercept point (IIP3) is larger than 16. 1dBm,with 50Ω as the source impedance. The input referred noise is about 36μVrms. The measured group delay variation of the filter between 3 and 5MHz is only 24ns,and the filter power consumption is 3.6mW. This filter with the tuning system is realized easily and can be used in many wireless low-IF receiver applications, such as global position systems (GPS), global system for mobile communications (GSM). and code division multiple access (CDMA) chips.