Realization of Gm-C Filter with Accurate Tunable Frequency
截止频率精确可调跨导电容滤波器实现

This paper presents a new circuit to tune Gm value of transconductor accurately which employs switched-capacitor technique to change the bias current of transconductor. A third order elliptical function lowpass filter with accurate tunable frequency is designed using transconductor that is not only with voltage common-mode negative feedback, but also with varying bias-triode transistors to improve the linearity of this circuit. Simulated results show that the practical frequency response of the filter is very near to that of idealized circumstance by applying TSMC 2-poly 4-metal 3.3V power supply 0.35μm CMOS technology Spice model.