一种高线性化的CMOS共源共栅低噪声放大器

该文提出了一种由调谐电感和PMOS管构成的3阶互调失真吸收单元来提高线性度。它通过吸收输出端上3阶互调失真吸收单元电流信号来提高CMOS LNA的线性度。调谐该线性化单元中的电感可减小源简并电感型共源放大器中2阶非线性引起的3阶互调失真。采用SMIC 0.18μmRF CMOS标准工艺,设计了线性化的CMOS Cascode LNA和传统结构做对比。

A Highly Linearized CMOS Low Noise Amplifier

A third - order intermodulation distortion （IMD3） sinker composed of a PMOS FET and a tuned inductor is proposed for linearization of CMOS cascode LNA in this paper. The IMD3 sinker is connected to the drain node of the CS stage in the conventional CMOS cascode LNA, it absorbs IMD3 current on the drain node to improve the lin- earity of CMOS LNA. By tuning the auxiliary inductor in the IMD3 sinker, the IMD3 generated by 2nd order non - hnearity in the CS stage can be alleviated remarkably. A CMOS cascode LNA applied with an IMD3 sinker has been designed for verification of the proposed linearization method through the SMIC 0.18 μm RF CMOS process. Simulation done by the Agilent high frequency simulation tool - advanced design system, it shows a 10dB improvement of IIP3 was attained while a 1.3 mA extra current consumed, a 1.8dB reduction of power gain, and also a slight increase of NF at 1.57GHz and 1.8V supply voltage, as the proposed LNA compared with the conventional LNA.