Analysis of IM3 Asymmetry in MOSFET Small-Signal Amplifiers

作者：Kim Namsoo^*; Aparin Vladimir; Larson Lawrence E

来源：IEEE Transactions on Circuits and Systems I-Regular Papers, 2011, 58(4): 668-676.

DOI：10.1109/TCSI.2010.2089548

• LNA
• IM3
• linearity
• asymmetry
• CMOS
• MOSFET
• volterra series analysis

This paper describes and analyzes IM3 asymmetry issues for weakly nonlinear MOSFET Common-Gate(CG) and Common-Source(CS) architectures. Using a Volterra series analysis, the cause of IM3 asymmetry in CG and CS amplifiers is explained. The asymmetry between high-side and low-side IM3 products in the CG amplifier exhibits a larger amplitude difference at low-frequency offset than at high frequency offset, while the CS amplifier shows more asymmetry at a high frequency offset. The magnitude of the IM3 product asymmetry in the CS amplifier can be significantly higher than the CG amplifier. Methods of mitigating IM3 asymmetry are suggested for both CG and CS amplifiers. A 65 nm Si CMOS technology is used for the simulation verification of the results derived in this paper.

• 出版日期2011-4