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I wanted to make a 3S li-ion battery pack. I also wanted to use an AMS1117 5.0 and 3.3, but when I read the datasheet, it said, that it can work with maximum of 12V.

Would I kill my AMS1117 if I supply a voltage of 12.6V (3S Li-Ion) to it?

EDIT:

Yes, it can work with 3s lipo batteries

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    \$\begingroup\$ Yes. Choose a different regulator. \$\endgroup\$
    – winny
    Aug 29, 2020 at 7:42
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    \$\begingroup\$ Where in the datasheet it says that? Because it is completely different if it is characterized to 12V, or if that is the absolute maximum. In any case is not a good idea to run the regulator over 12V if the nominal range is only up to 12V. \$\endgroup\$
    – Justme
    Aug 29, 2020 at 7:46
  • \$\begingroup\$ But my datasheet says Vin max is 15V, so no problem entertaining 3 Lipos: advanced-monolithic.com/pdf/ds1117.pdf. You might like to check out the I/O diff graph to see if you are happy with them. WARNING: me just friendly hobbyist. No guarantee no nothing won't melt down or blow up. Good luck. Cheers. \$\endgroup\$
    – tlfong01
    Aug 29, 2020 at 8:04
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    \$\begingroup\$ Thank you all for your answers. I ordered quite a lot of them, and will see, what can I do, and what is the limit of mine, since I saw one module with limit of 10v, one AMS1117 with limit of 12v and @tlfong01 's datasheet with 15v... \$\endgroup\$
    – mytja
    Aug 29, 2020 at 8:24

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Yes, exceeding the spec is not good. It will probably work for a while. Or even forever. But a) no way to say for sure and b) if you build many circuits like that, you can never tell how many will fail.

The dumbest and, yet in this case still acceptable option I see is 2 series diodes before 1117 that will drop 1.2-1.6V. You could get away with one, but I'm just making sure you're not at the spec boundary. Of course, if you have some charging circuit, it will have to connect to battery before diodes. I assume you don't have high currents there since it's 1117, but still estimate heat output on the diode (VdropI~0.7I) to make sure the selected diode can take it. Also, take a diode with some headroom in terms of heat dissipation, rectifier diodes will work nicely.

Also, don't ever go to Absolute Maximum ratings. There is a recommended maximum in the datasheet, always look at that. You don't want to push things to the maximum. There are so many parts to choose from that you can always find a way to make things work stable and well within the spec.

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  • \$\begingroup\$ Hello, and thank you for your answer! I ordered 50pcs of them and will see, what I can do. \$\endgroup\$
    – mytja
    Aug 29, 2020 at 8:30
  • \$\begingroup\$ Update! They are tested and can do regulating up to 15V! :-) \$\endgroup\$
    – mytja
    Oct 10, 2020 at 18:24

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