International Rectifier (IR) has added the IRF4000, a 100V-rated device integrating four MOSFETs into a single Power MLP package for Power-over-Ethernet (PoE) applications. The reduced footprint of the new device equates to a space savings of up to 80%, or three square inches of circuit board area in a typical 48-port board.
The IRF4000 complies with 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.
"Considering that each port in a PoE card requires its own MOSFET, the IRF4000 significantly reduces part count over the alternative of using individual MOSFETs in the same circuit. Manufacturing can also be simplified, eliminating 36 component insertions in a 48-port system," said Carl Smith, marketing manager for networking and telecommunication products at International Rectifier.
The MOSFET in a PoE design operates like a hot-swap FET, transferring power from the power sourcing equipment to the powered devices in a controlled fashion, and must operate in the linear region through a demanding worst-case operating condition therefore requiring an extremely robust safe operating area (SOA).
The low transconductance silicon technology used in the IRF4000 combines with about 1 degree 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 new device is qualified to industrial moisture sensitivity level (MSL) 3. The IRF4000 is also compliant with the upcoming PoE Plus architecture for high power loads.
The new IRF4000 is available now. Pricing is US $2.00 each in 10,000-unit quantity.
