高精度Σ-ΔADC中的数字抽取滤波器设计  

Design of digital decimation filter for high resolution Σ-ΔADC

作　　者：吴笑峰[1] 刘红侠[2] 李迪[2] 胡仕刚[1] 石立春[2] 

机构地区：[1]湖南科技大学信息与电气工程学院,湖南湘潭411201 [2]西安电子科技大学微电子学院宽禁带半导体材料与器件教育部重点实验室,陕西西安710071

出　　处：《中南大学学报（自然科学版）》2010年第3期1037-1041,共5页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(60206006);教育部新世纪优秀人才计划项目(NCET-05-0851);教育部科技创新工程重大项目培育资金资助项目(708083);西安应用材料创新基金资助项目(XA-AM-200701)

摘　　要：设计1个应用于高精度sigma-delta模数转换器(Σ-ΔADC)的数字抽取滤波器。数字抽取滤波器采用0.35μm工艺实现,工作电压为5V。该滤波器采用多级结构,由级联梳状滤波器、补偿滤波器和窄带有限冲击响应半带滤波器组成。通过对各级滤波器的结构、阶数以及系数进行优化设计,有效地缩小了电路面积,降低了滤波器的功耗。所设计的数字抽取滤波器通带频率为21.77kHz,通带波纹系数为±0.01dB,阻带增益衰减120dB。研究结果表明:该滤波器对128倍过采样、二阶Σ-Δ调制器的输出码流进行处理,得到的信噪失真比达102.8dB,数字抽取滤波器功耗仅为49mW,面积约为0.6mm×1.9mm,达到了高精度模数转换器的要求。A multistage digital decimation filter for high resolution sigma-delta analog-to-digital converter （Σ-ΔADC） was designed. The filter was fabricated by a 0.35 μm process and operates at a voltage of 5 V. The filter consists of a cascade-integrator-comb （CIC） filter,a compensation filter and narrow transition-band finite impulse response （FIR） half-band filter. Due to the optimal design of the architecture and order and coefficient of filters at various levels,the decimation filter effectively reduces the circuit area and power dissipation. The decimation filter has pass band of 21.77 kHz,pass band ripple coefficient of ±0.01 dB and stopped band attenuation of 120 dB. Experimental results show that by processing the bit stream from a 2-order Σ-Δ modulator with an oversampling ratio of 128,a signal-to-noise-distortion ratio （SNDR） of 102.8 dB is obtained for the filter. The filter has a good performance and its dissipation powder is only 49 mW. The occupied die area is about 0.6 mm×1.9 mm. The filter well meets the demand of high resolution Σ-ΔADC.

关 键 词：Σ-ΔADC模数转换器 调制器 降采样 数字滤波器 

分 类 号：TN432[电子电信—微电子学与固体电子学]