off topic: DS1307 and crystal damage by heat

[Ed Arnold]

I am using a DS1307 in a project. Everything worked fine in developement. The code is solid. I have a battery back-up attached. Now, I recently got a run of production PCBoards and the crystal has a grounding pad to solder the casing to. I think it's a good idea to solder it to the pad, but now the DS1307 doesn't run. If it was a code problem or battery back-up problem then the SCL and SDA lines would be held high and nothing else would work. That is not the case here. So, the question is can I damage the crystal when I solder it in? What temp should I use on my solder station? I could not find any data sheets or info elsewhere. Maybe someone has a link to direct me to.

Thanks

Ed Arnold
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This message was ported from CCS's old forum
Original Post ID: 13869

[Dave Yeatman]

I don't know what crystal you are using but here are the soldering specs from CTS as a general reference.

Solderability:

63Sn/37Pb solder, 5 sec. @ 245�C using <<--------

RMA flux; 95\% coverage, minimum

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:=I am using a DS1307 in a project. Everything worked fine in developement. The code is solid. I have a battery back-up attached. Now, I recently got a run of production PCBoards and the crystal has a grounding pad to solder the casing to. I think it's a good idea to solder it to the pad, but now the DS1307 doesn't run. If it was a code problem or battery back-up problem then the SCL and SDA lines would be held high and nothing else would work. That is not the case here. So, the question is can I damage the crystal when I solder it in? What temp should I use on my solder station? I could not find any data sheets or info elsewhere. Maybe someone has a link to direct me to.
:=
:=Thanks
:=
:=Ed Arnold
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This message was ported from CCS's old forum
Original Post ID: 13871

[Brian Sherer]

Top side pads for crystal leads must be very small to prevent shorting between lead and case; this might only show up if the case were grounded where it used to be left floating.

Insulators are available from Bivar etc. The thin mylar type work fine and are very cheap by the 1000's.

Brian
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This message was ported from CCS's old forum
Original Post ID: 13895

[PCM programmer]

:=I am using a DS1307 in a project. Everything worked fine in developement. The code is solid. I have a battery back-up attached. Now, I recently got a run of production PCBoards and the crystal has a grounding pad to solder the casing to. I think it's a good idea to solder it to the pad, but now the DS1307 doesn't run.
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On page 8, paragraph 2, of Maxim (Dallas) appnote 58, it says
"Crystal cans should not be soldered to the PC board."
They say it may damage the crystal.
<a href="http://pdfserv.maxim-ic.com/arpdf/AppNotes/app58.pdf" TARGET="_blank">http://pdfserv.maxim-ic.com/arpdf/AppNotes/app58.pdf</a>
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This message was ported from CCS's old forum
Original Post ID: 13959