GPIO Current Specifications

[wjohns2574]

Hello,

I have a question about the nRF52840 device and the supporting documentation. I am trying to figure out the current ratings for the GPIO. On page 198 it states that typical current is 9mA and the max is 14mA. This seems awfully low. What is confusing is that in the next few pages, Figure 25, 26 and 27 show that the max drive/sink current is around 25mA.

I guess what I am trying to figure out is what's the max current allowed? I'm glad I decided to check this, I was about to try to drive a LED between 20 and 30mA.

[Turbo J]

The curves are still missing in the NRF52840 specs, but these should be very similar to those in the nrf52832 GPIO spec.

These curves show short circuit currents in the 25-30mA range with 3V VDD. The NRF chip should survive on or two completely shorted GPIOs - unless you use the 50mA VDDH regulator.

I don't think you can drive an LED with more than 20mA, as the voltage drop across the pin becomes too big. BTW: Modern LEDs are VERY bright at 20mA.

[Simonr]

I just want to add to Jörg's post for clarity. Sinking 20mA into one pin will be fine, but I wouldn't recommend much more than that. The effect of providing more than 20mA won't be that significant.

Best regards,

Simon

[wjohns2574]

Thanks for the feedback. Yea an LED isn't all that I'm trying to drive and I wasn't planning on going any higher than 20mA. The main purpose was to see what my max driving capability was per pin for power consumption calculations and to make sure I don't damage the chip.

Turbo J I'm not sure if I'm understanding your statement correctly about the curves still missing for the NRF52840. If you go to the datasheet here: https://www.mouser.com/datasheet/2/297/nRF52840_OPS_v0.5-1074816.pdf , on pages 198 to 200 you will see the GPIO specs with drive and sink strengths.

Thanks again for your responses.

[Turbo J]

That seems to bee an old PDF. Current PS Version in the infocenter is 1.1, and this version does not have GPIO curves.