【Circuit Standard Design】 VOOHU Electronics -- SPE Single Pair Ethernet Standard Circuit Reference

SPE Single Pair Ethernet Standard Circuit Design Reference

This solution is VOOHU Electronics’ standard solution for SPE Single Pair Ethernet. The company has focused on the field of communication electronic components for over 9 years, adhering to the business philosophy and service concept of “Choose VOOHU – Truly Reliable”, and providing comprehensive technical solution support.

More related content on this site:【PRODUCT BASIC INTRODUCTION】SINGLE-PAIR ETHERNET(SPE) CONNECTOR 、【Application Solution】SPE: Single-Pair Ethernet Solution

Solution Overview

1. Primary side wiring:

• Differential pair connection: The primary side of the Lan Transformer is connected to the differential pair.
• Decoupling capacitor: The primary side shall be connected to GND via a 100nF capacitor to ensure signal stability and integrity.

2. Secondary side wiring:

• SPE connection: The secondary side differential signals shall be connected to the pins of the SPE interface respectively.

• BOB Smith circuit: The secondary side shall be connected to a 75Ω resistor each, then to chassis ground via a 1nF / 2kV or higher capacitor. A 1206‑package SMD ceramic capacitor or a high‑voltage ceramic capacitor with wide lead spacing is recommended.
  
  

3. Grounding treatment:

• BOB Smith circuit: The circuit composed of the 75Ω resistors and the 1nF capacitor provides a return path for common‑mode signals, effectively filters common‑mode signals, improves electromagnetic interference (EMI), and suppresses surge currents to a certain extent.

• Decoupling capacitor: The 100nF capacitor filters high‑frequency noise, ensuring signal stability and integrity.

• High‑voltage capacitor: The voltage rating of the 1nF capacitor must reach 2kV or higher to ensure reliability under high‑voltage conditions.

4. Solution brief description:
This solution is developed based on Jinglue Semiconductor’s JL310x (100M) and JL311x (1000M) series. With 3.3V or 1.8V TVS protection, common‑mode suppression realized by a 2012‑package CMC, and then signal isolation and impedance matching via a 4532 x’fmr (transformer), communication can be established externally through VOOHU’s SPE connector.

Recommended Components

To achieve reliable Single Pair Ethernet (SPE) communication, this solution adopts a full set of core components from VOOHU Electronics:

• SPE connector: WHSPE00467 (2‑pin socket, rated voltage 60V/4A, board‑mount type).

• PHY chip: Jinglue Semiconductor JL3101 (100M) or JL3111 (1000M), supporting 3.3V/1.8V I/O voltage.

• Common‑mode suppression: 2012A series common‑mode choke (CMC).

• Signal isolation and impedance matching: 4532B series transformer (X’FMR).

• Interface protection: WHTA3V30P8B (3.3V bidirectional TVS, 0.8pF low capacitance, SOD323 package).

Note: The above solutions are standard designs for reference only. The final circuit design shall be based on on‑site requirements. For in‑depth support, please contact us free of charge.

Tel: 400-1048-018; E‑mail: wohu@wohu-tek.com

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