30. GDT for Ethernet Port Lightning Protection

Outdoor Ethernet cables to IP cameras are exposed to lightning. A surge on the cable pairs can destroy the Ethernet PHY chip and PoE circuitry, which are very sensitive semiconductors.

A GDT placed on each cable pair at the port entry absorbs the high-energy surge before it reaches the board. The 75V spark-over is above the maximum PoE voltage (57V per IEEE 802.3af/at), so the GDT stays inactive during normal PoE operation.

Outdoor Ethernet requires ≥10kA surge rating because the cable runs can be long and directly exposed to lightning-induced currents.

Required: 75V Spark-Over · ≥10kA (8/20µs) · 2-Pole · Surface Mount · Littelfuse · RoHS

Go to DigiKey.com → Circuit Protection → Gas Discharge Tube Arresters (GDT)

Apply these filters:

•  Voltage - DC Spark Over (Nom) → 75V
• Impulse Discharge Current (8/20µs) → 10kA or higher
• Number of Poles → 2
• Mounting Type → Surface Mount
• Manufacturer → Littelfuse Inc.
• Part Status → Active

Tip: Each Ethernet port has 4 cable pairs. You need one 2-pole GDT per pair. The user selects the correct single GDT component; the BOM quantity depends on the number of pairs to protect.

The filtered list will show matching parts. Before you pick one, check: Is it Active? Is stock available? Is the manufacturer reputable? Is a datasheet available?

Full checklist: How to Select a Safe, Production-Ready Component — EWskills Guide

➡ View Matching Parts — Littelfuse, GDT, 75V, ≥10kA, 2-Pole, SMD