Document 458 Flyback Transformers ForNationalSemiconductor LM5070 PoE Interface 7 Watt Flyback transformers for 7 W PoE applications Designed to operate in continuous mode at 250 kHz with an input of 36 72 Vdc 1500 Vrms isolation from primary and bias to secondary Core material Ferrite Terminations RoHS tin-silver over tin over nickel over phos bronze. Other terminations available at additional cost. Weight 3.85 g Ambient temperature <.