Wurth Electronics Midcom has released the WE-FB 3573 product line, a series of ten different isolated fly-back transformers to operate the Linear Technology LT3573 chipset. This chipset is for low power PoE applications, as well as applications in the automotive, medical or industrial fields. As the LT3573 needs no third winding or optoisolator for regulation, these fly-back transformers are newly designed for this device.

With no need for the optoisolator for output regulation, there are fewer components needed for this power supply solution. No optoisolator provides for a more stable regulation loop and will eliminate the issue of thermal aging, as the optoisolator will become less efficient over time.

The WE-FB 3573 and LT3573 power supply solution has 17 components, compared to 35 components for a similar regulator. Fewer components also indicate lower cost, smaller circuit board space and higher reliability.

The transformer series is low profile with all parts under 12mm height. The transformer series ranges from EP7, EP10 and EP13 core sizes. The series of ten transformers are for various target applications with output power up to 7 watts. The transformers are rated for -40°C to 125°C operation with 1.5kV hi-pot isolation voltage. All the transformers in the series have been designed to have a very low leakage inductance, which will minimize any voltage spikes at the primary when the output switch is turned off. The low leakage inductance maximizes the efficiency of the chipset.