HI there,

I am using behavior model for a receiver simulation.  Down converter is built with ac coupling cap and ideal switch.  It seems that the cap creates some hurdles for simulation to finish correctly.  The baseband signal is very small unless the cap is larger than 100pF.  

for IP3 and ip2 of RF amplifier, if cap is present as the load, the IM3 and IM2 does not follow the ideal slope especially when input signal is small.  

Does anyone have similar experience?  How to get around it?

thanks