Transformer aims to serve the new PoE standard

TDK has unveiled a new series of EPCOS transformers for the Power-over-Ethernet (PoE) applications. These transformers are designed for an output of up to 60 W as per the requirements of the IEEE 802.3bt specification.

The existing systems — compliant with the IEEE 802.3af (PoE) and IEEE 802.3at (PoE+) standards — use two pairs of cables and are designed for outputs of 15 W and 30 W, respectively. On the other hand, the new IEEE 802.3bt (PoE++) standard, designed for four pairs of cables, has been developed to facilitate devices with higher power demand.

TDK’s new EPCOS transformers are designed to serve the applications specifically built around the new IEEE 802.3bt technology. These applications include POS systems, lighting controllers, fire alarm systems, and access control for smart buildings.

The B82806D0060A series of transformers comprises four types with different turns ratios for output voltages of 3.3 V, 5 V, 12 V, and 24 V. These transformers typically operate at the switching frequency of 250 kHz and are designed for a wide range of operating temperatures from –40°C to 125°C.

The electrical insulation of these RoHS-compatible transformers complies with UL 1446 class 130 (B). That allows them to withstand a high-voltage test between the primary and secondary sides at 1,500 Vac, 50 Hz for one second.

Next, the DC resistance values can be as low as 3.5 mΩ. That leads to higher efficiency and makes transformers more suitable for active clamp forward converter topologies. In these transformers, the SMDs have dimensions of 30 x 22 x 11.4 mm.