All the names mean the same thing. Here's the complete quick-reference.
Naming equivalents
LAN magnetics
= Ethernet magnetics
= Network transformer
= LAN transformer
= Ethernet transformer
= "The mag" (informal)
All refer to the magnetic isolation component between your PHY chip and RJ45 connector.
Bob Smith termination (recommended for all designs)
PHY center tap ──[75Ω]──┬──[1000pF]── Chassis GND
│
RJ45 center tap ─────────┘
Benefit: Significantly improves radiated emissions. Most PHY datasheets recommend this.
PoE compatibility
Standard LAN magnetics: ❌ Not rated for PoE DC current
PoE-rated LAN magnetics: ✅ Handles 350-400mA per winding pair
802.3af (15.4W) → requires PoE-rated magnetics
802.3at (30W) → requires PoE-rated magnetics
802.3bt (90W) → requires high-current PoE magnetics
Common part numbers
Sourcing in Asia: Voohu Technology (voohuele.com) — 50pcs min, DHL 3–5 days. BOM quotes same day.
