Question
I have stability problems with my ADL5331 design. Are there some general
suggestions from your site?
Answer
The ADL5331 stability is very sensitive to the layout of the output stage.
Great care must be taken to make the differential output layout symmetrical.
However, if a balun or transformer is used on the output, to convert to either
single ended or differential, the part behaves in a much more friendly way. I
suggest taking pin 4 of U4 and instead of connecting it to gnd, connect it to
OP- on the ADL5331. I have seen this work very reliably in the lab and we have
many other customers who have been successful implementing the 5331 this way.