一种消除直流失调的自动频率校准低通滤波器  

Automatic frequency-calibrated low-pass filter with DCoffset cancellation

作　　者：杨浩涵 乔树山[1,2] YANG Haohan;QIAO Shushan(Institute of Microelectronics of the Chinese Academy of Sciences,Beijing 100029,China;University of the Chinese Academy of Sciences,Beijing,100049,China)

机构地区：[1]中国科学院微电子研究所,北京100029 [2]中国科学院大学,北京100049

出　　处：《西安电子科技大学学报》2023年第1期85-92,共8页Journal of Xidian University

基　　金：国家重点研发计划(2019YFB2204601)。

摘　　要：为了改善直接变频发射机中由于模拟基带信号直流失调引起的本振泄露问题,以及低通滤波器截止频率因工艺偏差、温度变化和芯片老化而漂移的问题,提出了一种具有直流失调消除功能的自动频率校准低通滤波器设计与实现方法。该滤波器在串行外设接口控制模式下,通过可调电容阵列,可以将截止频率区间配置为324~648 kHz;在自适应调谐模式下,提出了一种基于锁存比较器的数模混合校准结构,通过校准芯片的RC时间常数,在不同环境温度条件下得到的截止频率为373.8~393.3 kHz,相对于标称值383 kHz的调谐精度约为-2.4%~2.7%。采用0.18μm CMOS工艺芯片进行流片生产验证,调谐电路面积为0.045 mm 2,仅占主滤波器面积的约2.2%。在1.8 V电源电压下,整个滤波器的功耗约为6.08 mW,输入参考噪声约为38.49 nV/(Hz)1/2。In order to improve the LO leakage caused by the DC offset of the analog baseband signal in the direct conversion transmitter,and the drift of the low-pass filter due to process deviation,temperature change,and chip aging,a method of design and implementation of an automatic frequency-calibrated low-pass filter with DC offset cancellation is proposed.In the SPI(Serial Peripheral Interface)control mode,the filter can configure the cut-off frequency from 324 kHz to 648 kHz through the adjustable capacitor array.In the adaptive tuning mode,a digital-analog hybrid calibration structure based on the latched comparator is proposed.By calibrating the RC time constant of the chip,the cut-off frequency is 373.8~393.3 kHz under different PVT conditions,and the tuning accuracy relative to the nominal value of 383 kHz is-2.4%~2.7%.The chip uses 0.18 CMOS technology for tape-out verification,and the tuning circuit area is 0.045 mm 2,which is only 2.2%of the main filter area.Under the 1.8V supply voltage,the power consumption of the whole filter is 6.08 mW,and the input reference noise is 38.49 nV/(Hz)1/2.

关 键 词：直接变频发射机 低通滤波器 直流失调消除 自动校准 

分 类 号：TN432[电子电信—微电子学与固体电子学]