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May 2007

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Tue, 8 May 2007 08:54:11 -0400
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TechNet E-Mail Forum <[log in to unmask]>, "Dehoyos, Ramon" <[log in to unmask]>
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	Steve:
	Yes, gold must be removed from SMT parts regardless. In a static
solder pot, it is very difficult, but fine pitch parts can be replated
by a miniwave with a N2 blanket. There is no need to dip it twice
neither due to the fact that the melt is moving.  It works very well and
it is done fast and no bridging. 
	Regards,
	Ramon

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Monday, May 07, 2007 3:15 PM
To: [log in to unmask]
Subject: Re: [TN] SMT connectors

Hi Phil!

We don't make choices regarding SMT connectors, our customers do, and I
can tell you I've seen a lot of different styles.

There's one thing about them that I've seen lately that I really don't
like, and it's mainly the SMT connectors that come from Samtec. Lately,
they been coming out with some high-density fine pitch designs that are
flash gold plated (RoHS compliant!), and that's the ONLY WAY you can get
them now. Flash gold is the RoHS finish of choice it seems for Samtec.
But now to comply with the J-STD, you must remove gold no matter what
the thickness on the solderable surfaces of SMT parts...right?

I've sent some samples of QSE and QTE series connectors to a company to
see if they can tin and remove the gold them for me. I hope they can,
but they may not be able to without a lot of bridging because of the
design of the connector. http://www.samtec.com/ftppub/pdf/QTE.PDF I just
know I don't want to try and do it myself.

I think this connector was a bad choice as far as reliability is
concerned (but I'm not the customer). These connectors are being used to
interconnect and stack with other boards, and there's no mechanical
support built into the connector other than the grounding strip that
runs down the middle of the connector. Plus we're putting down the big,
tall -07 lead style connectors (they're almost 1-inch tall!)

So really look at the connectors carefully. There's a lot out there and
they may seem like the perfect answer to eliminate a process step...but
be careful!

-Steve Gregory-  

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Nutting
Sent: Monday, May 07, 2007 11:05 AM
To: [log in to unmask]
Subject: [TN] SMT connectors

Hi Techies,

What choices have you made regarding SMT connectors?

We are designing some new SMT boards and could put SMT connectors on to
reduce or eliminate a wave or hand solder step.  I am looking at
D-subminiature connectors and 0.100 on center ribbon connectors.  Each
are available in SMT.  My concern is that the SMT is less durable in a
high usage or high vibration/shock environment.  Saving a step isn't
worth it if it created more long term failures.

Thanks in advance.

Phil

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