Ioan,
I said..some applications...not all. No big BGAs, no complicated edge connectors, no processors etc..just rather simple RF applications. You know how they look, few lines, wide lines, spacy, some LNAs, some biasing plastic ICs, some attenuators, a few power transistors, couplers, circulators...fresh boards, no solder problems. After mounting, sprayed with acrylic or other organic stuff, depending on how critical electrical fields we have to do with.
The below resistivity list explains some:
Cu 1.5 uOhm.cm hunting fractions of dBm
Ag 1.6 dominating since decades in many applications
Gold 2.4 reliable
Nickel 7.4
Sn 9.9
Sn60 18.0
ENIG >50
Optimal finish..hmm..think RF people have their different ways.
One of many papers in the GHz jungle: "Effects of surface finish on high freq signal loss using various substrate materials" . Not covering all needs, but give you an idea. Right on..no hieroglyphs. Call Don Cullen at Mac Dermid or Larry Gatewood at Rockwell Collins for a copy. As both companies have members in TN, I'm sure they will see this mail and assist interested persons. The table above is partly from their paper.
Ingemar
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Tempea, Ioan
Sent: den 16 maj 2005 15:04
To: [log in to unmask]
Subject: Re: [TN] FW: Possible Lead
Hi Inge,
guess you saw it coming, how do you control this? Cu oxidizes like hell, etc... Shelf life? How JIT is your JIT? NO No-clean?
Thanks,
Ioan
> -----Original Message-----
> From: TechNet [SMTP:[log in to unmask]] On Behalf Of Ingemar Hernefjord (KC/EMW)
> Sent: Monday, May 16, 2005 1:59 AM
> To: [log in to unmask]
> Subject: Re: [TN] FW: Possible Lead
>
> In some applications we have no finish at all! Copper is a superb RF conductor in itself.
> With other words: back to basics.
> Ingemar Hernefjord
> Ericsson Microwave Systems
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]
> Sent: den 13 maj 2005 21:28
> To: [log in to unmask]
> Subject: [TN] FW: Possible Lead
>
>
> Question:
>
>
>
> What is the optimal surface finish for PCBs working in the frequency band
> 10-15 GHz?
>
>
>
>
>
> Charlie McMahon
>
> McMahon Sales Company
>
> P.O. Box 1024
>
> Windham, New Hampshire 03087
>
> Tel: 603-432-3111
>
> Fax: 603-432-6854
>
> Cell: 603-401-4646
>
> e-mail: [log in to unmask]
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>
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