Ghost Tweaker
Member level 5

Hi everyone,
I have an LNA whose output is matched to 50Ohm over a small frequency range (LC matching). The stage following the LNA is a filter who is designed to work with 50Ohm load at input and output. Now outside of the band of interest, the LNA is not matched to 50Ohms and therefore the filter doesn't see 50Ohm anymore! Is it a concern? Should I use a resistive pad to smooth out the mismatch? I have recently seen many designs (discrete designs) using this technique. I was wondering if it is really necessary...
Thanx for your help
I have an LNA whose output is matched to 50Ohm over a small frequency range (LC matching). The stage following the LNA is a filter who is designed to work with 50Ohm load at input and output. Now outside of the band of interest, the LNA is not matched to 50Ohms and therefore the filter doesn't see 50Ohm anymore! Is it a concern? Should I use a resistive pad to smooth out the mismatch? I have recently seen many designs (discrete designs) using this technique. I was wondering if it is really necessary...
Thanx for your help