4
\$\begingroup\$

I'm intending to reflow solder some components from Analog Devices. Since they are an LFCSP package, hand-soldering is not possible. They arrived with a warning that they are moisture sensitive (MSL3) and require baking at 125 degrees for 24 hours before reflow soldering.

My question is, as a hobbyist with limited equipment, how can I safely remove the moisture? I don't have access to a reflow oven, only a kitchen oven (and it's not feasible to cook components in that for 24 hours, I am not even sure if that would be safe).

Alternatively, is the risk of popcorning that great? I only intend to make one or two prototype boards, and I have 6 ICs so could afford to sacrifice one or two.

\$\endgroup\$
4
  • \$\begingroup\$ You could always try putting them in a bag if rice for a few days. \$\endgroup\$
    – Trevor_G
    Mar 22, 2017 at 21:25
  • 3
    \$\begingroup\$ Usually this kind of chip is sold in a sealed bag and with an indicator card which will tell you if you need to bake it or not. Is it the case? \$\endgroup\$
    – bobflux
    Mar 22, 2017 at 21:27
  • \$\begingroup\$ If I put them in a bag of rice, aren't I risking ESD damage? \$\endgroup\$
    – Batperson
    Apr 6, 2017 at 3:28
  • \$\begingroup\$ The chips were free samples, so no sealed bag or indicator card. \$\endgroup\$
    – Batperson
    Apr 6, 2017 at 3:28

1 Answer 1

Reset to default
1
\$\begingroup\$

I wouldn't worry about it too much, I would try a one or two and see if you have a problem. I've never seen any pop-corning (the building that I usually reflow is about 30% humidity however, in a more humid environment 60%+ it might be a different story).

It would also depend on the cost of the component, if they were a few dollars its probably not worth your time for a bake out and to just go for it. If these are tens of dollars components, I'd take every precaution to make sure they are happy.

If its a MEM's device I might consider it because I do know people that have hand reflowed and had issues with devices working (we wern't sure it was ESD so we did humidity and ESD control and the problems went away), just put it in an oven at 125C for 24hrs if your worried about it.

By the way, you can use a hot air gun with LFCSP and hot air guns are relatively inexpensive. However, the humidity rules still apply with hot air guns.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.