Maximize the efficiency and reliability of your Power over Ethernet (PoE) applications with Infineon's cutting-edge solutions for power supplies for PoE

The cutting-edge technology enables you to design power supplies that are both space- and energy-efficient for even the most demanding PSE applications.

With advancements in technology and new PoE industry standards such as IEEE 802.3bt, one can now deliver up to 100W via Power over Ethernet - but this presents a unique challenge when it comes to designing main power supplies for PoE power sourcing equipment (PSE). To meet these challenges head-on, Infineon’s resonant SMPS topologies with efficient high-power MOSFETs enable keeping the same system size while increasing the available power budget per PoE port.

Benefits of power over ethernet

One of the biggest advantages of PoE besides having data and connectivity run over a single twisted-pair Ethernet cable (saving a traditional AC power cord) is that it allows centralization of power management. With traditional power systems, each device has its own power supply, which consumes energy even when the device is not in use. With PoE, however, all devices can be powered by a single central power source, which can be turned off or managed when not in use, reducing energy waste.

Because of the centralization, PoE enables also remote management of power. This means that devices can be powered on or off remotely, and their energy consumption can be monitored and centrally managed from one location such as the building management system. This not only increases energy utilization but also provides more control and flexibility over a building's power supply.

PoE also provides a more reliable and secure power supply. Traditional power systems are often prone to power outages and surges of the AC grid, which can damage devices and impact their performance. With PoE, the power supply is centralized and can be supported by an uninterruptible power supply (UPS), providing a more stable power source for connected devices, e.g. for surveillance cameras.

Overview of typical requirements for IEEE 802.3bt-compliant PoE PSE:

  • Higher output power as with every additional port up to 100W of needed power is added to the PoE power budget
  • Multi-stage SMPS designs with PFC, DC-DC main stage, rectification plus OR-ing if required
  • Increased power density to keep the existing form-factor despite an increasing output power
  • High efficiency for broad load conditions of the main power supply
  • For PoE PSE port MOSFETs, high efficiency through low RDS(on) and reliability through wide Safe Operating Areas (SOA)

Design benefits about Infineon’s OptiMOS™ 5, OptiMOS™ 6 & CoolMOS™ P7 family

Due to the increased power level per port with the latest IEEE 802.3bt standard, the respective power level of the main power supplies for PoE PSE applications has to increase as well. MOSFETs with a voltage rating between 40 V and 100 V depending on the typical system voltage are used to provide the OR-ing function when combining multiple power stages in PoE power supplies for PSE. However, for synchronous rectification on the secondary side of the power supply before the OR-ing stage, due to the typical PoE voltages of 44 V to 57 V normally 80 V and 100 V OptiMOS™ 6 MOSFETs are considered to keep reliability while keeping highest system efficiency.

On the primary side, superjunction MOSFETs such as Infineon’s CoolMOS™ family enable highest efficiency, cutting-edge performance with high robustness and reliability for converting the AC voltage to DC. The product family 600 V CoolMOS™ P7 SJ MOSFET offers highest efficiency and improved power density due to the significantly reduced QG and EOSS levels, as well as optimized RDS(on) making it ideal for PoE PSE applications.

The carefully selected integrated gate resistors enable very low ringing tendency, and, due to its outstanding robustness of body diode against hard commutation, it is suitable for hard, as well as so switching topologies, like LLC. In addition, the feature of an excellent ESD capabilty helps to improve the quality in manufacturing. The 600 V CoolMOS™ P7 offers a wide range of RDS(on)-package combinations, including THD, as well as SMD devices, at an RDS(on) granularity from 24 mΩ to 600 mΩ and comes along with the most competitive price/performance ratio of all 600 V CoolMOS™ offerings.

Explore the recommended products

Highlight product

The N-channel ISZ113N10NM5LF 100 V OptiMOS™ 5 linear FET, provides the robust performance required in Power Sourcing Equipment (PSE) ports for reliably powering connected powered devices.
ISZ113N10NM5LF guards against in-rush current surge and short circuit and enables higher protection and system reliability

Features of ISZ113N10NM5LF
  • Wide Safe Operating Area (SOA)
  • 11.3 mΩ maximum RDS(on) resistance
  • 63 A maximum continuous drain current ID
  • N-channel MOSFET
  • Typical 3.1 V gate threshold voltage (normal level)
  • Fully qualified according to JEDEC for industrial applications
  • 100% avalanche tested

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