Noise and Nonlinearity Modeling of Active Mixers for Fast and Accurate Estimation

• Published in: IEEE transactions on circuits and systems. I, Regular papers Vol. 58; no. 2; pp. 276 - 289
• Main Authors: Wei Cheng, Annema, A J, Croon, J A, Nauta, B
• Format: Journal Article
• Language: English
• Published: IEEE 01-02-2011
• Subjects: Active mixer; Capacitance; dc offset; flicker noise; IIP2; IIP3; Impedance; Integrated circuit modeling; intermodulation; mismatch; Mixers; Noise; nonlinearity; Resistance; Transistors
• ISSN: 1549-8328; 1558-0806
• DOI: 10.1109/TCSI.2010.2072110

This paper presents a model of active mixers for a fast and accurate estimation of noise and nonlinearity. Based on closed-form expressions, this model estimates the noise figure, IIP3, and IIP2 of the time-varying mixer by a limited number of time-invariant circuit calculations. The model shows that the decreasing transistor output resistance, together with the low supply voltage in deep-submicrometer technologies, significantly contributes to the flicker-noise leakage. Design insights for low flicker noise are then presented. The model also shows that the slope of the LO signal has a significant effect on IIP2, while it has a little effect on IIP3. A new IP2 calibration technique using slope tuning is presented.