一种高线性Gm-C复数滤波器的设计

针对低电源电压Gm-C复数滤波器线性度不足的问题,提出了一种使用大信号线性化技术的一阶复数带通滤波器。所提出的复数滤波器使用了不平衡差分对和自适应偏置电路两种线性化技术,通过扩展跨导相对恒定的输入电压范围提高滤波器的线性度。滤波器采用UMC 110 nm CMOS工艺设计,中心频率和带宽分别为2 MHz和1 MHz。Cadence仿真结果显示,在1.2 V电源电压下,滤波器功耗为229μW,镜像抑制比(IIR)为18 dB,线性度(输入三阶交调点IIP3)为9.53 dBm,总谐波失真(THD)为-55.7 dB。该复数滤波器电路结构简单、功耗较低,以期能广泛应用于低电源电压的接收机设计。

Design of a high linear Gm-C complex filter

To improve the linearity of the low-voltage Gm-C complex filter,a first-order complex band-pass filter was proposed using a large-signal linearization technique.The proposed complex filter is achieved using two linearization techniques,an unbalanced differential pair technique and an adaptive bias circuit.The linearity of the filter was improved by extending the range of the input voltage of transconductance.The filter was designed with UMC 110 nm CMOS process,and the central frequency and bandwidth are 2 MHz and 1 MHz respectively.The Cadence simulation results show that the power consumption of the filter is 229μW,the image rejection ratio(IIR)is 18 dB,the linearity(input third-order intermodulation point IIP3)is 9.53 dBm,and the total harmonic distortion(THD)is-55.7 dB.The complex filter circuit has a simple structure and low power consumption,which could make it widely used in receiver design at low power supply voltage.