With the continuous improvement of Ethernet rate, parasitic parameters effect can not be ignored on the electrical properties of therefore, Ethernet electromagnetic compatibility (EMC) and protective design of the key equipment to carry out the function of. EMC and the design of the protection of the design of the time, the lower the cost, the lower the cost. Not much nonsense, small love to do the most things that electronic engineers FAE tage experience for everyone to share, the Ethernet port lightning surge protection scheme of sharing is a rare practical dry cargo worthy of collection.

Design of lightning surge protection scheme for Ethernet port:
The design of Ethernet protection scheme takes into account the residual voltage after the lightning surge and the ceramic discharge tube level protection, therefore generally uses GDT to do in front of the common mode transformer (eight lines) surge protection; and low junction capacitance, fast response time, taking into account the protection of electrostatic function of TVS differential mode energy absorption tube.

Fast Ethernet protection scheme (a)
Protection circuit diagram:

The use of electronic devices to:
Ceramic gas discharge tube:
GDT [UN1206-200ASMD] DC nominal voltage 200 + 30%V, the impact current (8/20 s) 0.5KA, the capacitance value of < 0.5pF, resistance > 100M.
GDT [UN1812-90CSMD] DC nominal voltage 90 + 20%V, the impact current (8/20 s) 2.0KA, the capacitance value of < 1.0pF, resistance > 1G.

Transient suppression diode TVS tube:
TVS [Vrwm:2.8V] SLUV2.8-4, Vb:3.0V, anti-static capacity (contact / air): 8KV/15KV, junction capacitance (f=1MHz): 2.0pF, package: SO-08.

Fast Ethernet protection scheme (two)
Protection circuit diagram:

The use of electronic devices to:
Ceramic gas discharge tube:
GDT [UN1206-200ASMD] DC nominal voltage 200 + 30%V, the impact current (8/20 s) 0.5KA, the capacitance value of < 0.5pF, resistance > 100M.
GDT [UN1812-90CSMD] DC nominal voltage 90 + 20%V, the impact current (8/20 s) 2.0KA, the capacitance value of < 1.0pF, resistance > 1G.

Transient suppression diode TVS tube:
TVS [Vrwm:3.0V] ESD03V32D-LC, Vb:4.0V, anti-static capacity (contact / air): 8KV/15KV, junction capacitance (f=1MHz): 1.2pF, package: SOD-323.

Gigabit Ethernet protection scheme (1)
Protection circuit diagram:

The use of electronic devices to:
Ceramic gas discharge tube:
GDT [UN1206-200ASMD] DC nominal voltage 200 + 30%V, the impact current (8/20 s) 0.5KA, the capacitance value of < 0.5pF, resistance > 100M
GDT [UN1812-90CSMD] DC nominal voltage 90 + 20%V, the impact current (8/20 s) 2.0KA, the capacitance value of < 1.0pF, resistance > 1G.

Transient suppression diode:
TVS [Vrwm:2.V] SLUV2.5-8, Vb:3.0V, anti-static capacity (contact / air): 30KV/30KV, junction capacitance (f=1MHz): 3.0pF, package: SOP-08, ultra low leakage current

Gigabit Ethernet protection scheme (two)
Protection circuit diagram:

The use of electronic devices to dance:
Ceramic gas discharge tube:
GDT [UN1206-200ASMD] DC nominal voltage 200 + 30%V, the impact current (8/20 s) 0.5KA, the capacitance value of < 0.5pF, resistance > 100M
GDT [UN1812-90CSMD] DC nominal voltage 90 + 20%V, the impact current (8/20 s) 2.0KA, the capacitance value of < 1.0pF, resistance > 1G.

Transient suppression diode:
TVS [Vrwm:3.0V] ESD03V32D-LC, Vb:4.0V, anti-static capacity (contact / air): 8KV/15KV, junction capacitance (f=1MHz): 1.2pF, package: SOD-323.