Help in dealing with OP AMP susceptibility to RFI

[Nicholas]

My voltage follower is sensitive to strong RFI under EMC test. Output a voltage offset under RFI. Anybody has experience in dealing with this kinda problem. Please help. THanks!!!

 

[goodboy_pl]

maybe the voltage follower is unstable or have a low phase margin

1. if it is wide band(10MHz and above), check the datasheet for possible min gain
2. check for feedback components and parasitics
3. try to decrease the physical size of the circuit

BEST!

 

[rfsystem]

Simple: Rectifying effect on the input stage lead to an offset shift. That is a 30 year old known problem. If there is an OpAmp you can try to apply the RF to both inputs. But for a voltage buffer the inverting feedback input is not accessable. So filter down the RF before input.

 

[vale]

an EDN article maybe helpful
/http://www.edn.com/article/CA333616.html

 

[artem]

Post is old but may still be actual so ...

In book below there are one or two pages with practical recomendations for opamp, that will really help you :


and also this article is for /http://www.edn.com/article/CA333616.html
is for HF RF immunity not UHF.

 

[artem]

Links below were provided but little bit outdated so use search goolgle to find newest:

**broken link removed**

these are worth to read , especially design techniques parts