nRF52, Li-polymer battery OK?

[Ladasky]

I have a PMIC in the device that I am building which will eventually take over from the battery. But I have to program the PMIC on startup, using the nRF52. I am trying to minimize the need for analog switches and crazy power routing.

The specifications for the nRF52 state that the maximum VDD is +3.9V. I have seen documents which describe the maximum voltage from a lithium polymer battery to be exactly that 3.9V value.

I have four sample Li-poly batteries which have voltages written on them by the factory, ranging from 3.814 to 3.821V. However, with a voltmeter, I'm getting up to 4.18V from a fully-charged pack. Is this a problem? I know that the voltmeter is a very light load, and that the voltage will drop once the load increases. Still, I wonder whether I would be endangering my device by operating directly from a fresh battery.

Thanks for your assistance.

[RK]

Read this devzone.nordicsemi.com/.../, it's not really 3.9v, it's really 3.6v. The maximum voltage from a fully-charged LIPO is 4.2V, don't know where you got 3.9V from, that's usually the nominal voltage or about the 1/2 way point of discharge. Your voltmeter experiment seems to confirm that.

You can't power the nRF52 directly from a LIPO.

[Ladasky]

Thanks for the links, Øyvind.