TDK Corporation is presenting a new series of EPCOS transformers designed for an output of up to 60W, which are suitable for PoE++ according to IEEE 802.3bt. The new B82806D0060A series comprises four types with different turns ratios for output voltages of 3.3, 5, 12, and 24V. The SMD components have dimensions of 30x22x11.4mm 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 1,500VAC, 50Hz 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 15W and 30W, 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.