60W Transformers for PoE++ Designed for Outputs from 3.3V to 24VMarch 01, 2018 by Paul Shepard
TDK Corporation has added a new series of EPCOS transformers designed for an output of up to 60W, which are therefore suitable for PoE++ according to IEEE 802.3bt. The new B82806D0060A series comprises four types with different turns ratios for output voltages of 3.3V, 5V, 12V, and 24V. The SMD components have dimensions of 30mm x 22mm x 11.4mm and are designed for a wide range of operating temperatures from -40 °C to +125 °C.
The electrical insulation of the RoHS-compatible transformers complies with UL 1446 class 130 (B) and can withstand a high-voltage test between the primary and secondary sides at 1500 V AC, 50 Hz for one second.
Particularly worth highlighting are the low DC resistance values that – depending on the type – can be as low as 3.5mΩ. This results in a higher efficiency, thus making the new transformers also suitable for active clamp forward converter topologies. The typical switching frequency is 250kHz.
An increasing number of devices offer LAN connectivity for communication purposes. The obvious solution therefore is to power them via the LAN cable as well (Power over Ethernet), so that no separate power supplies are necessary.
Existing systems with two pairs of cables compliant with IEEE 802.3af (PoE) and IEEE 802.3at (PoE+) are designed for outputs of 15 W and 30 W, respectively. The IEEE 802.3bt (PoE++) standard, which is designed for four pairs of cables, has been developed in order to supply devices with a higher power demand.
The new EPCOS transformers are designed specifically for this application segment. Typical applications are video and POS systems, but also include systems such as lighting controllers, fire alarm systems or access systems that are used in building management.