Electronics > Beginners
Doesn't happen every day.. IC package destroyed while hot air soldering.
JPortici:
So i am assembling three prototypes where i used a MCP16311 buck converter. I had four left from a past project, and they were kept inside the tape, inside the antistatic bag.
None of them works. It's not a circuit problem, as i literally copy-pasted the power supply from the previous project, and triple checked.
Then this happened, i was removing one of the chips using hot air and tweezers. The package was destroyed.
I have soldered hundreds, even thousands of chips this way. Something like this never happened to me.
Out of ideas, all of the chips fails the same way (vfb doesn't rise above 0.2V, switcher doesn't switch, Vdd is 5V with a little pulse on it)
Semiconductor crime scene photos i guess
Ranayna:
The only thing I can think of would be moisture absorption. That could easily crack the casing when hot-air soldering.
Were these the oldest stock you ever used?
JPortici:
I am suspecting moisture as well. Now i will try and mount one of these in a working board and vice versa..
Another really nasty photo
Benta:
Yep, moisture popcorning. You might be able to save them by baking.
RoGeorge:
After a while, the case absorbed moisture from air. In the original bag should be a moisture indicator.
To avoid future cases cracking, you need first to slowly bake the ICs (in order to slowly remove the moisture before proceeding to soldering), then solder the baked ICs with hot air or an oven.
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