MOSFET Drives PoE Designs

The IRF4000 100V MOSFET for power-over-Ethernet (PoE) applications provides significant board-space savings, in the area of three square inches for a typical 48-port board, by integrating four HEXFET MOSFETs into a 10 mm x 5 mm x 1.85 mm MLP. Obviously, this approach reduces part counts over the typical method of deploying individual MOSFETs for each port. The device employs low transconductance silicon technology and exhibits a thermal resistance of approximately 1°C/W. It is both electrically and thermally characterized under worst-case, IEEE 802.3af-specified operating conditions, guaranteeing a 56% higher safe operating area when compared to single SOT-223 MOSFETs. In addition to meeting IEEE 802.3af requirements, the IRF4000 complies with the emerging PoE Plus architecture for high-power loads. Other features include on resistances of 270 mO and 350 mO at gate-to-source voltages of 12V and 10V, respectively. Pricing is $2 each/10,000. For more details, contact Wayne Yoshida at INTERNATIONAL RECTIFIER, El Segundo, CA. (310) 252-7726.