nRF52840 Powering

[e_g_loco]

Hello,

We are developing a smart padlock with nRF52840 on  Raytac MDBT50Q-1MV2. It will be powered from CR2 type battery.

We will support two types of battery chemicals,
Lithium-ManganeseDioxide 3V Full - 1,5V depleted
Lithium-ThionylChloride 3.67V Full - 3.5V depleted

Soc is rated 3.6V recommended operating voltage and 3.9 absolute maximum voltage.

Lithium-ThionylChloride is 0.07 above this recommended voltage. I am wondering what is the side affects of using 0.07V higer than recommended voltage.

For example,
Do some TVS diodes start to leak?
Does it shorten expected life 5%?

Is there a recommended circuit for utilizing such batteries?

[Bendik Heiskel]

Hi,

When using VDD above 3.6V the life time will decrease and the performance equal to the spec can not be guaranteed.

If both battery types are used then an external regulator would be needed.

Lithium-ManganeseDioxide battery can be used with normal voltage mode, with VDD and VDDH shorted together.

For the Lithium-ThionylChloride battery you can use high voltage mode, by supplying only VDDH from the battery.

Here are the different configurations for the internal regulators:

https://infocenter.nordicsemi.com/topic/ps_nrf52840/power.html?cp=4_0_0_4_2_0_3#unique_1591758884

 

Best regards,

Bendik