Continuing my PoE series, I bought the ONV PD3401G, an active PoE splitter that is capable of extracting up to 60W (24V @ 2.5A) from the PSE. It is housed in a small aluminum extruded case that can be DIN rail mounted. This splitter is comparatively low-cost, about US$35, and more importantly, is capable of passing through Gigabit.
ONV seems to be quite a reputable company, so I believe their products shouldn’t be too badly designed. This unit can also be easily purchased on Aliexpress without having to go through some obscure distributor.
Internally it uses the LT4275A (marking
LTGBT) for PD interfacing. The
A variant of this chip supports up to 90W of power. On the power supply side, it uses a NCP1034 synchronous buck converter. The NCP1034 is capable of handling up to 100V, which is more than sufficient for PoE.
Looking inside, the in/out Ethernet ports are connected via a transformer, in order extract power from the center taps of each pair. We can see that the PCB traces for the input port pairs are thicker to carry the higher currents. Large beefy diodes form rectifier bridges for the data pairs.
Surrounding the input port on the underside, there are a lot of unpopulated components; those were supposed to offer input protection, probably using some TVS of some kind. these are marked
RD8, one for each Ethernet wire.