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Subject:
From:
"Ingemar Hernefjord (EMW)" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Wed, 22 Mar 2000 10:45:30 +0100
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Thanks Mike,
would like some demo pictures if you have..//Ingemar

-----Original Message-----
From: Michael Fenner [mailto:[log in to unmask]]
Sent: den 18 mars 2000 12:26
To: TechNet E-Mail Forum.; Ingemar Hernefjord (EMW)
Subject: Re: [TN] Tantalum capacitors


This body design is preferable to the previous which looked like two tailed tadpole and gave all
sorts of problems with bleed and very low joint strengths. If you can't solve the problem with
careful shaping of the glue shape prior to placing and placement pressure/pad design such that
the adhesive squidges into correct place (rather than out of it) then you could consider
striping non conductive adhesive between pads to make a dam bar and stand off. Alternative is to
dot insulating adhesive as well as conductive so that  on co curing component is held by both
adhesive types. This is usually OK for high G.


Mike

----- Original Message -----
From: Ingemar Hernefjord (EMW) <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, March 17, 2000 9:57 AM
Subject: [TN] Tantalum capacitors


>
> Now, about tantalum caps. Anyone out there using tantals with FLEXIBLE terminals? Old model,
you recognize that, is with a more or less straight and painted body, terminals silvered, tinned
or gold plated, most models for soldering. New since a number of years are those with
rectangular body, suitable for P-P, and with sort of flexible ribbon terminal that is bent 90
degrees under the body. Those having these are e.g. Kemet, Sprague, Matsuo, Tekelec, Siemens,
NEC, AVX/Kyocera to mention some.  OK, they are all excellent for soldering, but for silver
epoxy mounting a minor problem occurs: the epoxy wets, not only the terminal but also the body.
Then you loose some of the advantage with flexibility. You find a typical outline in IPC-SM-782
Subsection 8.4.
>
> Question: anyone that pick-and-place such creatures for silverepoxy technology? What terminal
finish do you order? And do you utilize the flexibel terminal?  How do you get a recommende
epoxy line (50-100um) as the component is heavy, do you use some kind of standoff? Anyone that
has centrifuged up to 5,000 G's? Anyone with experience from mounting such caps on
Arlene/Roger/Taconic with heavymetal backing?
>
> Normal FR4 indoor products with this cap are normally soldered and there are no obstacles. So,
we don't have a general problem, but lack some experience for epoxying in special applications.
>
> Also will come back later with discussion about ceramic caps, ferro/piezo effects, aging and
such things that has been up recently. Ousten, France, are you out there? Still working with the
RFceramic characterization project? Lost your e-mail adress.
>
> Ingemar Hernefjord
> Ericsson Microwave Systems

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