Electronic – Need help identifying an SMD component – top marking PJt

I imagine there are a bunch with the same pinning. They usually call this package a SOT-23-6 (for 6 leads..).

Generally you'd want 100V or so for PoE switch, for when the mosfet lets go of the coil, it will spring up some. If there is some snubbing maybe not too much, but I think 100V would be a safe bet.

What IC is used to control the FET? They usually are current mode and will sense the current in a small resistor from the switching FET's source to ground, <1 ohm usually. If we know the sense resistor and the SMPS IC, we can figure what the maximum current is also, to select a fet. :)

Edit: maybe I misinterpreted - is this switching the primary of the transformer? or just randomly somewhere in the circuit on the primary side? Might be for enabling PoE power to downstream parts, for example, after uh.. initiation. In that case, the protocol IC most likely limits current too - have to see it's datasheet to see if it switches the high side or the low side, etc.

The part is connected to pin 5 of the USB connector, which is the 5V supply from USB. It is most likely to be a fuse: either a PTC resetable fuse or a non-resettable fuse. Its marking are consistent with a SMT fuse, although to understand the marking you would need to know the manufacturer of the fuse. It is unlikely to be an inductor or ferrite bead, since those parts are usually unmarked.

After the fuse is a diode of some sort connected between the 5V supply and Ground. This is probably a TVS diode to protect the device against voltage transients.

If you follow the PCB trace it then passes through part which is probably a ferrite bead which is used to reduce EMI emissions. SMT ferrite beads are usually unmarked.