Max input voltage for "Adafruit Feather M0 Adalogger"

Other Hardware 3rd Party Boards
1

The voltage regulator says "G3P" - as far as I can tell.
Google leads me to a AP2112 voltage regulator, but I have no idea if that is really the used regulator.
Adafruit doesnt provide information about the regulator or the voltagelimits, so im asking if anyone here knows about it?
Is 6.5V the max voltage?

Since I would like to only have one powersupply Im going to use 12V. So I want to avoid a extra 5V or another 3.3V regulator. If i have to use one: Any ideas where to get good (low quiescent current) regulators? Would it make sense to use a buck-converter for the requiered ~20mA average? Or would they waste too much at those low currents?

2

Well, a converter can be 85-90% efficient, yes?

While a linear regulator dropping from 12V to 5V is less than 50% efficient.

The converter costs more, like $4.50 at /www.pololu.com

It's an engineering trade-off you have to make.

3

Adafruit M0 Adalogger
https://learn.adafruit.com/assets/29013
shows this for the 3.3V regulator

It can take 12V, but will likely get warm if you try powering more than the board with it.

4

Well, a converter can be 85-90% efficient, yes?

Sure, but with a quiescent current of lets say 10mA the efficiency is going down the drain.
Or am I wrong and there are efficient converters for low currents?

While a linear regulator dropping from 12V to 5V is less than 50% efficient.

Sure, it will be ~5/12 efficiency. But its just ~10mA and not battery powered. So it doesnt matter. It has to work and be reliable.

A SPX3819-3.3 - brilliant, it can take 16V!
How did u find that document? I googled and searched their site and found nothing regaring this at all...
Saves me some trouble, thanks.

I just noticed the V_DD for the LiPo-charger-IC. It says 3.75-6V and is right on V_Bus with the input of the regulator. Specsheet says 6V max too. Seems like I need to protect it... maybe cut a trace or desolder it.