Why are my S3A pins getting destroyed?

I have a S350A VQFP100 on my custom board, with all the pins connected to large pads all around the chip.

I have destroyed 3 pins, total. Two pins can't be used as inputs anymore, and the third lost tri-state ability. BTW, the pins are in two VCC banks.

True, my soldering tip is not grounded, but the last pin was destroyed a few days ago, and I didn't physically touched the pad it is connected to for at least 3 months.

First two pads I did touch a lot with my soldering tip while testing, so I can believe that it was destroyed by ESD. At that time, I have also soldering 10 other pads near those two, but they didn't die.

But what about that third pin? It is a part of the data bus (D2), located in top bank, and it hasn't been touched by soldering tip or even the scope for at least 3 months.

So, why did it die?

Reply to
aleksazr
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Damn it, I've found the error, the wire is badly soldered.

Reply to
aleksazr

And fixing one wire is worse than having to replace a whole FPGA?

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Reply to
Tim Wescott

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