The IRF4000 from International Rectifier is a 100V-rated device integrating four HEXFET MOSFETs into a single Power MLP package for Power-over-Ethernet (PoE) applications. The device complies to the IEEE 802.3af specification for networking and communications infrastructure systems, such as Ethernet switches, routers and hubs, delivering up to 15W per port, replacing four individual SOT-223-packaged MOSFETs. The reduced footprint equates to a space savings of up to 80%, or three square inches (19.35cm2) of circuit board area in a typical 48-port board. As each port in a PoE card requires its own MOSFET, the device reduces part count over the alternative of using individual MOSFETs in the same circuit. 

The low transconductance silicon technology used in the IRF4000 combines with about 1°C/W package thermal resistance to enable efficient removal of heat while operating in the linear region and has been fully electrically and thermally characterized under worst case IEEE 802.3af operating conditions. The new device guarantees a 56% higher device safe operating area compared to individual SOT-223 MOSFETs, improving system reliability and thermal margin. In addition to 48-port systems, the IRF4000 is ideal for 96-port applications or for smaller PoE “jack companion” modules using 12-ports where, in each case, four ports can be addressed with a single IRF4000 device. The device is qualified to industrial moisture sensitivity level (MSL) 3. The IRF4000 is compliant with the upcoming PoE Plus architecture for high power loads in addition to the IEEE 802.3af specification.