Class 8 Power over Ethernet (PoE) Powered Devices

The Si34071 PoE Powered Device (PDs) combines an IEEE 802.3bt interface and a high efficiency DC DC controller into a single IC. Configurable for class 4 – class 8 power, the Si34071 simplifies high power PoE designs for wireless access points, small cells, security cameras, and smart lighting. It supports the key new features of the 802.3bt specification including short maintain power signature (MPS), autoclass, and power demotion. A UART port provides a simple interface for the system controller to enable/disable MPS pulse generation and determine the power granted by the PSE. The integrated DC DC controller supports flyback or forward topologies. The DC DC’s peak current mode control and variable switching frequencies improve efficiency and reduce EMI. Combined with easy to use EVBs, the Si34071 provides a complete solution for designing the new generation of PoE Powered Devices.

Package size
5x5 mm
Maximum output power
71 W

Class 8 Power over Ethernet Common Specs

  • Fully IEEE compliant 802.3bt interface supports
    • Class 4 – 8 4-pair power
    • Short maintain power signature (MPS)
    • Autoclass
  • Integrated DC DC converter supports flyback or forward topologies
    • Peak current mode control
    • Low-EMI slew rate control
    • PWM switching frequency control
  • External hotswap and switching FETs improve thermals
  • Comprehensive protection circuitry
    • Internal transient voltage suppressor
    • Under voltage lockout
    • Thermal shutdown protection
    • Short circuit protection


  • Transformer winding efficiency enhancer
  • UART interface to system controller

Jump Start Your PoE Powered Device Development

PoE Powered Device (PD) design involves achieving IEEE compatibility and creating an efficient, stable, and EMI compliant power supply. Our complete portfolio of evaluation boards (EVBs) offer complete PD designs ready to be incorporated into an end system. All of our PoE PD EVBs are EMI compliant and include an IEEE compatibility report, detailed power supply performance analysis, and schematics in the user's guide.

Find the Right Class 8 90W Device Select Columns
Select Columns
Part Number Description IEEE Specification Maximum Output Power (W) Package Type Package Size (mm) Aux Transformer Winding Input DC DC Efficiency (%) Switching Frequency Range (kHz) Temperature Range (°C)
PoE PD IEEE 802.3bt (Type 3 & 4) Compliant Interface 802.3 bt Type 3 and 4 71 QFN32 5x5 90 100 500 -40 85

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