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.
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.
| Series | Size |
VDC (V) |
CCh typ. (pF) |
|---|---|---|---|
| WE-TVS | DFN1210 | 3.3 | 0.18 |
| Series | Size |
Z @ 100 MHz (Ω) |
IR. (mA) |
|---|---|---|---|
| WE-CNSW | 1206 | 2200 | 200 |
| Series | Size |
VT (V(DC)) |
L (µH) |
|---|---|---|---|
| WE-STST | 1812 | 2250 | 350 |
| Series | Name | Size | C |
VR (V(DC)) |
|---|---|---|---|---|
| WCAP-CSMH MLCCs | C1 | 1206 | 1 nF | 2000 |
| WCAP-CSGP MLCCs | C2 | 0402 | 100 nF | 50 |
| WCAP-CSGP MLCCs | C3 | 0603 | 100 nF | 100 |
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.
Useful links:
- To the product catalog of Würth Elektronik eiSos: here
- Current article at elektroniknet.de (in German): Standard industrial interface for Single Pair Ethernet
- Webinar Recording: Single Pair Ethernet - Filter Design