一款应用于多模式无线发射机的65nm可配置低功耗滤波器

A Reconfigurable Low Power Filter in 65 nm CMOS for Multi-standard Transmitters

针对多模式(GSM/TD-SCDMA/WCDMA)无线发射机设计了一款可配置的4阶有源RC低通滤波器。滤波器的截止频率通过数字配置运放外围的无源器件进行改变,从而满足不同模式的带宽要求;同时,滤波器中运放的增益带宽积(GBW)也进行相应的配置,实现滤波器的低功耗设计。针对后者,对滤波器中运放的增益带宽积对滤波器的传递函数的影响进行了定量的分析,提出了功耗优化理论。整个电路结构是在65nmGP工艺下实现的,电源电压为1V,芯片核的面积仅为0.08mm2。滤波器在三个模式下测试得到的IIP3均大于25dBm。整个电路的功耗在GSM和TD-SCDMA下为0.8mW,在WCDMA模式下为1.6mW。同时,滤波器在三个模式下传递曲线的测试结果证实了文中的功耗优化理论。

This paper presents a novel approach to design a programmable 4^th-order low-pass reconstruction filter for GSM/TD-SCDMA/WCDMA wireless transmitters. With a view to opti- mizing power, reconfiguration is used to digitally adjusting the filter cut-off frequency. Additionally, a theory is proposed to provide a lower limit of the gain-bandwidth product （GBW） of OPAMP used in the filter, and therefore, its power can he optimized. The filter is realized in a 65 nm GP CMOS technology with the area of 0. 08 mm^2. The measured in-band IIP3 is beyond 25 dBm for the three modes motioned above. The measured power consumption is 0. 8 mW for GSM and TD-SCDMA setting and 1.6 mW for WCDMA setting. The filter transfer function is also measured, which strongly supports the proposed theory.