1mA power draw from nRF52840 when asleep, but not off

RE: 1mA power draw from nRF52840 when asleep, but not off

Stian Røed Hafskjold — Mon, 08 Feb 2021 17:34:44 GMT

Some peripherals will draw current in the 10-20 uA range when not completely disabled. This includes slave peripherals like the SPIS, TWIS and UARTE. The SPIM should not consume any extra current when not transmitting. In this case it's only because of the errata.

RE: 1mA power draw from nRF52840 when asleep, but not off

Gordon — Mon, 08 Feb 2021 13:44:02 GMT

Thanks - that's great news! Just gave this a try and it shaved a good 700uA off the power draw. I hadn't previously bothered turning off peripherals like SPI when the device sleeps - should I? Or in this case is it just because of that errata?

RE: 1mA power draw from nRF52840 when asleep, but not off

Stian Røed Hafskjold — Mon, 08 Feb 2021 11:41:29 GMT

Hi, First thing that comes to mind is errata 195. It was introduced on the nRF52840, so it's not present on the 832. It also fits well with the 0.95 mA current draw. It would also go away when entering system OFF.

Please have a look here and check if it could be relevant:

https://infocenter.nordicsemi.com/topic/errata_nRF52840_Rev2/ERR/nRF52840/Rev2/latest/anomaly_840_195.html?cp=4_0_1_0_1_26

The regulator design is pretty much the same as on 832, except if you are using the high voltage (VDDH) input. But it should not cause 1mA of current draw anyways.