Hello Ian, There are ESD suppressor components offered for RF applications, but of cou= rse they are highly dependent on the frequency, power, impedances etc. in= volved. These parameters were not detailed in your post, so with a stab i= n the dark for a small device with not very high frequency, there might b= e a relevant device at=20 http://www.spkecl.com/htdoc/over-voltage-protector-ESD-Guard.htm or there a= re other similar offerings from Littelfuse or Bussmann and others. ...but this wasn't your question. You hinted at having a solution yourself= , which involves removing the inductor. I have to agree. It's always tr= icky to make a meaningful comment without knowing the details (and I'm no= t an expert), but I don't see how the inductor could provide an ESD solut= ion in that configuration, unless the frequency of transmission is very h= igh and it is guaranteed that there is not much ESD energy at frequencies= approaching that. Ever. The noteworthy thing is that the most likely failure mode of the inductor i= s open, which might keep the device operating, but it can then be (perhap= s fatally) damaged by the next serious ESD event that comes along. What actual (physics based) explanation has your colleague offered for the = inductor, apart from that all ESD experts use it? It suspiciously sounds= like it is something that is appropriate under some specific circumstanc= es, and has then been applied because "experts do it". People can get to= uchy when they are asked about something they've done that they don't tot= ally understand why... Of course, we never see that on this forum!!! ;-= ) Regards, Sandor Daranyi Senior Design Engineer Ian Barrett wrote: > I am currently having a lively discussion with a colleague about an ESD > problem we have encountered. The trouble is I don't think either of us=20 > know > enough to be able to convince the other of our point of view. > > The product is a small radio transmitter that is very susceptible to=20 > an ESD > spike applied directly to it's antenna. The design includes a small > inductor > between the antenna output and ground. My colleague (the designer) put it > there to try and alleviate any potential ESD problems. I have found > that I > cannot solve the ESD susceptibility problem without removing it. > > He claims 'any ESD experts will tell you to place this inductor' and > wants > me to try and find another solution to the problem. But I think the > inductor > is making the situation worse by coupling the ESD spike onto the ground > plane. > > Can anyone offer some theory to back up either argument? > > Ian. ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu