Cascading 2 RF LNA, do I need to AC-couple them? Does DC-bias stays the same?

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I've used a single LNA and biased it according to specs. Now, if I want to put 2 of them in series, do I need to AC couple RF lines between them? Do I need to change my DC-bias?
 



If I want to put another LNA, do put a cap between them?
 

Do your amplifying stages consist of transistors? There is the handy trick of alternating N devices and P devices. Each stage can bias the next stage at correct polarity. No need for series capacitors.
 

No, it's a monolithic amplifier, everything is matched to 50Ω.
 

As above ^^^

Usually the spec sheet tells you if its dc to xxx Mhz, if so then its certainly dc coupled all the way through and will require external coupling capacitors.

If it has internal coupling capacitors, it much more likely to mention a minimum (but fairly high) operating frequency in the specification.
 

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