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?