Discussion Forums

IoT pHAT power pins


I’m looking at connecting a Pi Zero with the ioT pHAT + an RMF69 radio module over SPI (see sparkfun or adafruit for examples).

I’m customizing a 2x20 header so that the total stack height is minimal.

What pins does the IoT pHat use for power? I was hoping to use pins 17 and 25 to power the RFM69, but don’t know if that’s what is used by the IoT pHAT…

Thanks in advance!


look at chart on github,


Yeah, I’ve seen and studied that chart - but that does not answer the question I had in mind. So let me rephase it:

Which pins actually supply Vin and GND to the IoT pHAT board?

I don’t need a list of which pins can potentially supply Vin and GND…


luckily, in this case i have a 50-50 chance of selecting the correct power pin. personally, i would take the pin that would give you the shortest power wire, assuming you are not going to mount the module on the pins themselves since that would break the one phat per rpi rule. also, best isolation between antennas should be a concern i would imagine. i’d like to see some pictures of the project if possible. my guess is redbear uses pin17, but unless you are worried about noise on the power line you probably can use it.


Potato quality photo here:

Basically pulling pins out of the 2x20 header so that I can run silicone wire from the RFM69 radio module to directly solder them to the pi zero.

Still hoping someone ( @cheong ?) can chime in with what pins are used for power and GND!


yup, if pulling pins you absolutely need the info.


The IoT pHAT gets power from the RPi 5V (see the pinout diagram, there are two 5V pins) to the onboard LDO and supplies 3.3V to the WiFi/BT module, all the GND pins are connected altogether.


But can it be the other way around? Can the IoT pHAT power the Pi Zero using the pHAT pins?


Just provide power to one of the 5V pin from the 40-pin header.