nrf52805 temperature >85degc

[victor passe]

Hi, do you have plans to test the nrf52805 at 105 degC or higher, similar to nrf51822 Extended Industrial Temperature range document

We will probably run the NRF52805 at higher temp any way and do our own testing but are there any specific things we should worry about at for example 105degc? flash retention? radio out of spec?

[ketiljo]

The radio may be out of spec, general current draw will be higher and the flash retention is reduced. Probably down to a year at 105 degrees.

[victor passe]

what failiuremode will flash retention give? will the bits tend to become a 0 or become a 1?
Eg, can we solve it by just rewriting every page every year without eraseing?

[ketiljo]

The cells in the flash will lose the charge so they will flip to 1. 

You could solve this by rewriting the flash but you have to erase first. But you will lose the calibration data that stored in FICR https://infocenter.nordicsemi.com/topic/ps_nrf52805/ficr.html. This is a part of the flash that can only be written to by the factory tester.