Re using an IC

The VNH5019 is a hearty motor driver I’ve been using, but currently out of stock at Digi-Key and mouser.

Here is the chip:
https://www.digikey.com/product-detail/en/stmicroelectronics/VNH5019ATR-E/497-13073-1-ND/3455763
I have one on another board that I reflowed in a reflow oven last year but never used because the board has other design flaws. If I bake the board in my oven at about 150 degrees for 24 hours, then remove it with my hot air gun, I shouldn’t really hurt the integrity of the chip, should I? I don’t want it to fizzle out on me in a couple years.
Thanks.

If I bake the board in my oven at about 150 degrees for 24 hours,

Seems a bit hot, look at the maximum storage temperature in the data sheet. Also look at the temperature profile for soldering.

I would be inclined just to take it off with the hot air gun.

Grumpy_Mike:
Seems a bit hot, look at the maximum storage temperature in the data sheet. Also look at the temperature profile for soldering.

I would be inclined just to take it off with the hot air gun.

I agree. But I think we would lay a line of solder across ALL the pins on one side and then use the hot air gun to melt all the solder at once and lift the side with tweezers. Then do the same for the other side. Clean chip legs with soldering iron if necessary.

Paul

I'm more a fan of using a good coating of flux to pull a chip, along with the hot-air rework. If it's a large chip and I don't want anything else around it, I sometimes even heat it from the back with a hot-air gun. A blowdryer might even work from the back, but be cautious around any electrolytic caps. They might just pop with substantial force.

The chip is SOP-30, even smaller than a Atmega32U4. Should be easy to remove.

Depending on the equipment available, I would

  1. Cover the area around chip with Kapton tape to protect adjacent components (unless you don't care )
  2. Use a hot air gun set to around 300-340 Deg C (higher if lead-free), preferably with a suitable SOP nozzle to heat the pins
  3. Lift the chip (or just push it away from pads) with a pair of tweezers the moment solder liquefies
  4. If you need to re use the PCB , put lots of flux rosin on the pads and use de-soldering braid with soldering iron to clean the rosin residue. This is best done before the PCB cools down.Then use alcohol pads to clean the rosin left.

I ve used the above technique for chips upto TQFP64 with excellent results. Sometimes twice or even three times on the same PCB.

PS: I have used a re-flow oven before to completely strip components from a PCB but you have to follow the heating profile of the most sensitive component on board.

The baking step to remove moisture from the package reduces the chance of the package cracking due to steam formation during soldering/desoldering. I've never seen a single device fail this way, its only something to worry about when manufacturing complex boards (where a single device failing on a few percent of boards is economically noticable).

Just hot-air the chip off.

If you are in the USA, this kit worked for me

https://www.allelectronics.com/item/smd-1/smd-removal-kit/1.html