The new Nanos that are being released like the Nano 33 BLE are 3.3V instead of 5V. V_USB must then be regulated. What is the acceptable voltage range for V_USB? Does it need to be exactly 5V? On old Nano boards V_IN is regulated. What is the acceptable voltage range for V_IN with these new boards?
OK, I got some help looking at the schematics. It looks like these boards use an MPM3610 to convert the input voltage (either V_USB or V_IN if I'm interpreting it correctly) to 3.3V. Specs for the MPM3610 indicate it accepts an input of 4.5V-21V. I guess that means a LiPo battery is out.
Any suggestions for a simple battery power supply solution?
Thanks for taking the time to post an update with the information you found msdsmith! You're right about the 4.5V-21V range for VIN.
The simplest battery power supply solution would be a USB power pack. The only trick is that some of the more high end ones have an automatic cutoff that causes them to not turn on when a low current device is attached. You can work around that, but it's annoying to have to do it. You can also get boost converter modules to increase the LiPo battery voltage to >4.5 V from any place you would buy electronics parts from (e.g., eBay). The 5 V modules are very widely available and cheap due to being used in those USB power packs.
If that Nano and its peripherals can accept 4.2V (fully charged LiPo) you should be able to use a LiPo battery without any voltage regulator. Or power it through an external LDO regulator, there are regulators that have as little as 200 mV minimum drop.
The nRF52480's datasheet says the recommended operating conditions are Vdd of 1.7-3.6 V. So I don't think it's safe to directly attach a LiPo.
Thanks for the replies.
I can try to look into USB power pack options. I was hoping to use LiPo as we want to keep size to a minimum for our application.
It seems odd to have brand new 3.3V boards like this that aren't compatible with a LiPo battery.
That's where that suggested linear regulator comes in play. Maybe the board can't handle much higher voltages, it very likely can handle a bit lower voltages: the output will drop below 3.3V when the battery gets nearly exhausted.
msdsmith:
It seems odd to have brand new 3.3V boards like this that aren't compatible with a LiPo battery.
Why? LiPo batteries produce 3.2-4.2V. That's not 3.3V. Also most projects are not battery powered. Just add your own 3.3V regulator and you're there! There's no such thing as one size fits all in electronics. It's actually pretty neat for the developers to add a switching power supply to this board, most Arduino boards have a linear regulator.