一种基于FDDA的全差分Sallen-key低通滤波器

A Fully Differential Sallen-Key Low Pass Filter Based on FDDA

在传统Sallen-key低通滤波器的基础上,利用一个全差动差分放大器(FDDA),设计了一种新型的全差分Sallen-key低通滤波器。该滤波器能有效抑制共模噪声,大幅减少功耗。电路参数取决于电容之比和电阻之比,具有较高的精度。截止频率和品质因数独立可调,易于分析和设计。电路结构简单,通带增益范围广,无源灵敏度较低。相比传统的两个单端Sallen-key滤波器,该滤波器降低功耗达50%以上。采用0.18μm CMOS工艺进行设计,电源电压为3.3 V。仿真结果表明,功耗仅为532μW。在1 kHz频率下,输入参考噪声为542.9 nV·Hz^(-1/2)。

Based on the traditional Sallen-key low pass filters,a novel fully differential Sallen-key low pass filter was designed by using a fully differential difference amplifier(FDDA).The common mode noise could be effectively suppressed and the power consumption could be reduced by this filter.The circuit parameters depended on the ratios of capacitance and resistances,and had a high accuracy.The cut-off frequency and the quality factor could be adjusted independently,which were easy to analyze and design.The circuit had a simple structure,a wide pass-band gain range and a low passive sensitivity.Compared with the traditional two single-ended Sallen-key filters,the proposed filter could save power by more than 50%.It was designed in a 0.18μm CMOS process at 3.3 V power supply voltage.The simulation results showed that the power consumption was only 532μW.At 1 kHz frequency,the input referred noise was 542.9 nV·Hz-1/2.