Another session of blank stares into a datasheet.
First was the VBAT to 3V3 conversion, my first thought was the tps73020 because it’s super common in a lot of mesh builds. But even thought it’s alright it could be a bit smaller. We don’t need a stable 3V3 because the stm chip can do as low of 1.8V and 2.4V while vref and ADCs are active.
So I went with a buck topology that also has 100% duty.
UVLO is realized by a ti power management IC.
Gemini helped me a bunch with choosing the right components.

After that I need some kind of chager IC, it would be nice if the charger could also other chemistries, but I have only found one IC that would work great but that one wasn’t easily accessible on mouser so I’ve went with a LiIon only, which is fine for at least this devboard prototype.

And started work on the peripheral page.