When reviewing my component choice for a design based around the i.MX RT 1170, I noticed that the Wurth 7499211121A mag jack which I had taken from the MIMXRT1170-EVK schematic was a PoE jack. I thought that was strange as I wasn't using PoE and all the connections to the symbol had been used.
The PoE connections on this jack appear to be pins 9 and 10. On the MIMXRT1170-EVK, MIMXRT1160-EVK and possibly other evaluation kit schematics too, these pins are connected to the 3V3 and GND power rails, per the screenshot attached.
Why is it connected this way? Since PoE is 48V or more, wouldn't this blow up the evalation kit if accidentally plugged into a PoE line? Also, if connecting two EVKs together, I can't see how it would work if the expectation is that the 3.3V power rail of one board is used to power the other board over the ethernet cable?
Depending the standards A / B and if you are using 10/100/ 1000 are the POE pins
Regards
Which standard does the board use?
I'm not aware of any PoE standard which uses 3.3V.