FTM Board Club

The STEVAL-POE002V1 reference design is a two-stage converter for a powered device (PD), and is able to deliver up to 40 W (5 V/8 A) DC from appropriate 4-pair PoE power sourcing equipment (PSE), or an external auxiliary supply.

The first stage is the Ethernet interface is based on the PM8805 controller with integrated full active bridge rectification. The PoE controller is compliant with the third generation IEEE 802.3bt specification (as well as the preceding 802.3af/at standards), with improved features and increased power capacity that allow new application possibilities for PoE networks, including point of sales and retail logistics devices.
The second stage is the DC-DC converter designed around a fixed frequency flyback topology managed by the configurable PM8804 PWM controller, with secondary synchronous rectification via a gate driver transformer.

  • PM8805 4-pair IEEE 802.3bt compliant PD interface
  • Works with power supplied from Ethernet LAN cables or local auxiliary sources
  • Line input voltage range: 40 to 60 VDC
  • Output stage managed by configurable PM8804 controller
  • Output voltage: 5 VDC ±2.5%
  • Output current: 8 A
  • Peak-to-peak output ripple:
  • DC-DC full load efficiency: >91%
  • Overall full load efficiency: >90%
  • Transient response ΔV pk-pk 100% to 50% load step ≈ 700 mV
  • Switching frequency ≈ 280 KHz