On the validity of single-ended mixed-mode s-parameter measurements for differential active devices

This paper examines the differences occuring between virtual and true differential probing of active balanced devices in large signal region. The analysis is carried out by means of gain compression of single stage pseudo and true differential amplifiers. Based on analytical derivations, a simulation model for these amplifiers is developed and verified by measurement results. Finally, the reason for the deviation between virtual and true differential measurements is highlighted.