移动数字电视调谐器中低噪声模拟滤波器的设计  

Analog Filter Design with Low Noise for Digital Video Broadcasting-Handheld Tuner

作　　者：戚建烨[1] 王小力[1] 王守军 

机构地区：[1]西安交通大学电子与信息工程学院,西安710049 [2]IDT科技上海有限公司,上海200233

出　　处：《西安交通大学学报》2009年第2期72-76,共5页Journal of Xi'an Jiaotong University

基　　金：教育部科学技术重点资助项目(03151)

摘　　要：为了降低零中频移动数字电视调谐器中模拟滤波器的噪声,提出了一种新的基于低噪声运算放大器设计的技术.该技术通过对运放共模回馈小信号等效电路的分析,采用左半平面零点对电路进行稳定性补偿,在保证相位裕度的前提下优化晶体管尺寸,降低低频闪烁噪声.仿真结果表明,同优化前相比,该运放在1 kHz处的噪声系数降低约3.4 dB.应用该技术设计了一个8阶切比雪夫II型低通滤波器,该滤波器具有2.85 MHz、3.33 MHz、3.8 MHz 3种可编程带宽模式,在偏离带宽1.4 MHz处实现了45 dB衰减.芯片采用台积电0.18μm混合信号1P 6M CMOS工艺设计,面积为2.4 mm×0.72 mm.对电路进行了带版图寄生的后仿真,结果表明滤波器的噪声性能满足系统设计要求.To reduce the noise of the analog filter in zero intermediate-frequency digital video broadcasting-handheld tuner, a new design technique base on low noise operational-amplifier（Op-amp） is presented. The small signal model of Op-amp＇s common mode feedback circuit is quantitatively analyzed, and then a left-half plane zero is leaded into the common mode feedback loop to compensate the stability. The size of the transistor is optimized to reduce the flicker noise under a determinate phase margin. Simulation results show that the noise figure of Op-amp at 1 kHz frequency is decreased by 3.4 dB, compared with the unimproved technique. The proposed technique is used in an eighth order Chebyshev Ⅱ low pass filter that has three programmable bandwidths： 2.85 MHz,3.33 MHz,and 3.8 MHz, and the attenuation is 45 dB at offset of 1.4 MHz. The filter is implemented in Taiwan semiconductor manufacturing corporation 0.18 μm mixed signal 1P 6M CMOS process, which occupies a chip area of 2.4 mm×0. 72 mm. The post-layout simulation results show that the noise performance satisfies the design requirement of the system.

关 键 词：移动数字电视调谐器 低通滤波器 低噪声 

分 类 号：TN47[电子电信—微电子学与固体电子学]