Single Pair Ethernet

Single Pair Ethernet embodies a new type of data transmission. Contrary to Multipair Ethernet, only two wires are needed. The small number of wires ensures thinner cable diameters and reduces cost.

But what does this mean for the circuit on the PCB?

Have a look at our webinar recording " Single Pair Ethernet - Filter-Design".

Single Pair Ethernet from Würth Elektronik eiSos

Compact design

By using only one pair of wires, the number of passive components on the PCB is considerably reduced. Together with the very compact connector, Single Pair Ethernet can save up to 75 % PCB space, compared to current Ethernet over RJ45.

Insulation voltage according to IEC 62368-1

Similar to Ethernet over four-pair wires, isolation in accordance with IEC 62368-1 (formerly
IEC 60950) is also specified for Single Pair Ethernet. Capacitors with 50 Volt galvanic isolation apply almost exclusively to automotive Ethernet applications and are not sufficient for industrial applications.

The good news is that the electrical isolation in Single Pair Ethernet can be easily solved by a signal transformer. Our WE-STST transformer series combines excellent performance with a very compact size of only 4.5 x 3.2 mm.

Through connection of the centre tap to GND, common mode signals are also effectively attenuated

Additional EMI and ESD protection

In addition to the transformer (74930000), a common mode choke (744232222) improves the EMI behavior even at frequencies from 1 MHz without negatively affecting the data signal. The TVS diode (824012823) provides ESD protection according to IEC 61000-4-2 up to 8 kV.



Measurement results 10BASE-T1

Measurement results 100BASE-T1

Part list

TVS Diode
Series Size VDC
CCh typ.
WE-TVS DFN1210 3.3 0.18
Common Mode Choke
Series Size Z @ 100 MHz
WE-CNSW 1206 2200 200
Signal Transformer
Series Size VT
WE-STST 1812 2250 350
Series Name Size C VR
WCAP-CSMH MLCCs C1 1206 1 nF 2000
WCAP-CSGP MLCCs C2 0402 100 nF 50
WCAP-CSGP MLCCs C3 0603 100 nF 100

Resistor with 100 Ω (Size 0603)

Würth Elektonik is a member of the SPE Industrial Partner Network

The SPE Industrial Partner Network is an equal association of companies that promote Single Pair Ethernet technology as the basis for rapid and successful growth of the IIoT (Industrial Ethernet of Things).

For future users it is the first point of contact for all questions concerning the construction of SPE networks and devices. It provides clear recommendations for the development of future IIoT applications and is the central information and exchange platform.

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