Prabhu
Junior Member
![* *](https://designers-guide.org/forum/Templates/Forum/default/starblue.gif)
Offline
Posts: 23
|
I am trying to estimate the IIP2 of a double balanced gilbert cell mixer. To model the transconductor mismatches I am using dc voltage offsets at one of the gates. I have also introduced mismatch in the load resistor. I did a sweep QPSS analysis with two equal tones (f1 = 2.45 GHz, f2 = 2.455 GHz ) and LO = 2.443 GHz When I plot the IP2 curves the slope of the f2 - f1 component is close to 3 instead of 2. But when I plot the single ended output current of the mixer at f2 - f1 it shows the proper second order behaviour ( slope = 2 ). Once I take differntial output the slope becomes close to 3.
What could be the reason for this strange behaviour?
thanks Raja Prabhu
|