I just wanted to update previous similar questions for the nRF52 series, old one for nRF51 is here: devzone.nordicsemi.com/.../
At page 151, section 20.4, of the nRF52832 Product Specification v1.0 I find that GPIOs configured as high drive can source a maximum of 14mA and sink a maximum of 15mA, if VDD >= 2.7 V.
What is the limitation of the total current we can source/sink at the same time in multiple pins? For example in nRF51 you could have 3 pins sourcing 5mA at the same time, so maximum 15mA.
These max values are for steady constant currents rigth? Just wanted to confirm.
At the table we can find min, typ, max values. Do they mean that due to fabrication differences, some chips' pins will only be able to source 6mA instead of 14mA?
If number 3 is true, what happens if we try to source 14 mA from a pin that only supports 6mA? Will it break or will it limit this current to 6mA?
Looking at next page of the document, page 152, from graphs I get higher values for these currents, around 25mA. What is the difference or what am I missing?
Thank you very much,
Edit: minor changes to make it more clear
We recommend 15mA total current sink/source on the chip for normal operation. This can be on one pin if you want (different than nRF51). We recommend that you sink current rather than source current because of more ground pads than vdd pads.
Thank you for the answer. Is that a real specification or still something that has to be tested and 15mA is to make sure we are on the safe side? I find it quite low. :( For example in my case I have a very low power RGB led, 5mA each led. If it goes full on it is already 15mA, so it could be risky to even charge N mosfet gates using other gpio pins at the same time?
One more question, if I combine sink and source pins, is it safe to go a bit higher than 15mA suming sink+source? For example sink RGB leds and source N mosfet gates.
Going a bit over 15mA will probably be ok. This is a recommended number as the real number will depend on alot of things specific for each pcb design. If you sink 15mA you should be able to source N mosfet gates (if this requires low current).
Make a look on the LED: SML-LX0404SIUPGUSB It is a very bright one and maybe you could save current a little bit.