Connecting ground pad on 64LQFP XS1-L1

Technical discussions around xCORE processors (e.g. General Purpose (L/G), xCORE-USB, xCORE-Analog, xCORE-XA).
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rp181
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Connecting ground pad on 64LQFP XS1-L1

Postby rp181 » Sat Dec 18, 2010 12:17 am

I don't have access to a reflow oven, so I was wondering how to best connect the center ground pad. I am currently trying conductive silver epoxy, but I am unsure if it will work as it may present a couple of ohms of resistance.

I also a product called kopr-shield, a copper suspension in a petroleum based product. It worked well without vaporizing on my railgun, so I assume the resistance is quite low.

Suggestions?
bearcat
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Postby bearcat » Sat Dec 18, 2010 5:47 am

Solder from the back side is quite easy if you can get a hole in your PCB. The example PCB shown in the post below is for the L1-64. I might think drilling a hole in a finished PCB would be an option.

See the following post:
forum/viewtopic.php?f=7&t=608
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leon_heller
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Postby leon_heller » Sat Dec 18, 2010 2:10 pm

That's how I do it on prototypes using QFN chips - I put a large via in the centre. I heat it with the soldering iron tip and feed solder into the hole.
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rp181
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Postby rp181 » Sat Dec 18, 2010 11:18 pm

That was my thought too, but I made the via too small :)
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leon_heller
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Postby leon_heller » Sun Dec 19, 2010 4:21 pm

Drilling it larger should work, if you haven't soldered the chip.

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