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Stability of AD8331 LNA (with input filter)

Question asked by 6j5 on Aug 15, 2011
Latest reply on Sep 2, 2011 by 6j5

The AD8331 data sheet recommends and 120nH ferrite + Csh net at the LNA input for stability reasons.


I would like to insert an antialias filter (AAF) right at the LNA input ( something like an eight pole 50 ohm filter) cutting off at 30MHz but have concerns over impact on LNA stability with this filter and the 8331 LNA active termination (50ohm). 


Has any one any experience in this area using the 8331?   Unfortunately the LTspice modelavailable  for the 8331 does not include the LNA section (only the VGA).