RE: External I2C bus communicating when nRF9160 is powered down

Håkon Alseth — Fri, 17 Jan 2020 14:55:37 GMT

Happy to help. Let us know if you have any more issues or questions.

Hope you have a nice weekend!

Cheers,

Håkon

RE: External I2C bus communicating when nRF9160 is powered down

calebsmyth — Fri, 17 Jan 2020 13:54:18 GMT

Thank you for your advice Håkon, much appreciated.

Caleb

RE: External I2C bus communicating when nRF9160 is powered down

Håkon Alseth — Fri, 17 Jan 2020 11:36:09 GMT

Hi Caleb

[quote user=""]My question is, if the nRF9160 is powered down, not in sleep, completely powered off, and there is activity on the I2C bus, does this have the potential to damage the nRF9160 as the SCL and SDA lines would be switching between 0V and 3V3.[/quote]

If the nRF is powered off (ie: VDD = 0V) these two I2C lines will try to power the nRF via the protection diodes inside the pad, and thus draw current.

Due to this, you will then exceed the maximum ratings: https://infocenter.nordicsemi.com/topic/ps_nrf9160/abs_max_ratings.html?cp=2_0_0_11

I would recommend that you isolate the I2C lines (level shifter that you disable or similar) if you want to continue with this solution.

Kind regards,

Håkon