【摘要】 提出了一种改进的高线性度、宽调节范围的可调跨导运算放大器(OTA).其采用输入衰减和交叉耦合差分对两种线性化技术实现高线性度.此外采用源级退化电流镜结构对跨导值进行调节,实现了20倍的调节范围,同时保证了调节过程中维持相同的输入电压幅度.为了验证该OTA结构的有效性,设计了一个3阶低通滤波器.电路采用0.18μm SMIC CMOS工艺模型,仿结果显示,滤波器实现了从600 k Hz到10 MHz的线性调节,电流消耗为0.9-1 m A,其IIP3最高24.8 d Bm.更多还原

【Abstract】 An improved operational transconductance amplifier(OTA) with high linearity and wide tuning range is presented. Two linearization techniques, input attenuators and cross-coupled double differential pairs,are employed to achieve high linearity. Moreover, the source-degenerated current mirrors structure used to achieve the wide tuning range of the transconductance, guarantees the proposed OTA a 20 times relative tuning range without decreasing the input voltage-swing. A 3 rd-order low-pass filter(LPF) is presented to verify the effectiveness of the proposed topology of the OTA. Simulated with the 0.18 μm SMIC CMOS process, the post-layout simulation results showed that the LPF exhibits a linear tuning capability from 600 kH z to 10 MHz with a low current consumption of 0.9-1 m A. The in-band IIP3 is up to 24.8 d Bm.更多还原