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44. GDT for Ethernet Port Lightning Protection

Neha is designing a PoE-powered industrial Ethernet switch installed in a building with outdoor cable runs to IP cameras. 

The Ethernet cables are exposed to lightning-induced surges on the cable pairs. 

She needs a GDT for each cable pair at the Ethernet port entry as primary surge protection to absorb high-energy surges before they reach the Ethernet PHY and PoE circuitry. 

Key requirements: 

  • PoE voltage on cable can be up to 57V 

  • GDT spark-over voltage: 75V (above PoE voltage, fires only on surge) 

  • Surge current: ≥10kA (8/20µs) for outdoor lightning-class protection 

  • 2-pole GDT (one per cable pair) 

  • Surface mount package 

The company's AVL specifies Littelfuse, so the part must be selected from Littelfuse on DigiKey. 

2-pole-SMD-GDT

Help her select a suitable GDT from Littelfuse on DigiKey. 

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