In home broadband and industrial communication scenarios, xDSL equipment is constantly connected to the PSTN public network line. It is highly susceptible to overvoltage and overcurrent surges caused by lightning strikes, AC power crossovers, power line induction, or switching surges. Inadequate protection can lead to communication interruptions or even complete equipment damage.

Therefore, a robust circuit protection scheme is crucial for ensuring the stable operation of xDSL equipment.

❓ Why do xDSL devices require multi-level protection?

xDSL devices typically include:

  • AC/DC power module
  • Broadband DSL interface
  • PHY physical layer chip
  • USB interface
  • RJ45 / RJ11 interface
  • SoC main control system

These interfaces are directly or indirectly connected to external lines, making them most vulnerable to lightning strikes and surges.

⚠ Major sources of risk include:

  • Lightning surges
  • Power line induction
  • AC power accidental contact (Power Cross)
  • Electrostatic discharge (ESD)
  • Plug-in/out transient impacts

Therefore, a zoned, multi-level, low-capacitance, and highly reliable protection design is essential.

Below is a detailed introduction to the application of our electronic components in xDSL devices.👇

Surge and ESD Protection Solutions for xDSL-Protection Devices-TVS Diodes-ESD Protection devices-Gas Discharge Tube-Thyristor-Pled Protectors-Mov

1️⃣ AC/DC Power Input Protection Solution

In the AC/DC power supply section, voltage regulation and clamping protection are particularly important.

Recommended Devices:

➡️ BZT52B5V1 – 5.0~5.2V Zener Diode (SOD-123, 500mW)

https://en.semiware.com/zener-diodes/bzt52b5v1

🔹 Functions:

  • Precise voltage clamping
  • Protects downstream PFC, DC/DC, and LDO circuits
  • Absorbs transient overvoltage surges

🔹 Advantages:

  • SOD-123 small package
  • Fast response speed
  • Cost-friendly

2️⃣ Broadband DSL Line Protection Solution

DSL lines, directly connected to the public network, are the most vulnerable to surge damage and must be protected with multi-level protection.

Recommended Devices:

➡️ Gas Discharge Tube (GDT) - SG3225B800 – 800V, 1KA, 0.5pF

https://en.semiware.com/gas-discharge-tubes/sg3225b800

Functions:

  • Absorbs high-energy lightning surges
  • 0.5pF ultra-low capacitance, does not affect DSL signal quality
  • Suitable for high-speed broadband signal lines

➡️ Low-capacitance ESD diode - GBLC03CI – 3.3V, 0.6pF, ±30KV

https://en.semiware.com/esd-diodes/gblc03ci

Functions:

  • 0.6pF ultra-low capacitance, ensures signal integrity
  • ±30KV electrostatic discharge protection
  • SOD-323 small package, saves PCB space

➡️ TVS array - SRV05-4A – 5V, ±15KV, 0.8pF

https://en.semiware.com/esd-diodes/sesrv05-4a

Functions:

  • Multi-channel protection
  • Fast response
  • Suitable for DSL differential line protection
  • High-reliability surge suppression

➡️ High-reliability surge suppression - P4200SC – 400V, 6KV, 100A high-reliability thyristor

https://en.semiware.com/thyristor-surge-suppressors/p4200sc

Functions:

  • High impact resistance
  • Can withstand 6KV surge protection
  • Suitable for harsh environments

3️⃣ PHY Interface Protection Solution

The PHY chip is the core of DSL communication; it is costly and sensitive to signals, requiring careful protection.

Recommended Devices:

➡️ Dual-channel programmable protector - STP61089B – 167V, 3KV, 70A

https://en.semiware.com/programmable-protectors/stp61089b

Functions:

  • Dual-channel design
  • High surge withstand capability
  • Suitable for DSL line protection

➡️ Quadruple-channel programmable protector - STP61089Q – -167V, 2KV, 40A

https://en.semiware.com/programmable-protectors/stp61089q

Functions:

  • Multi-channel integration
  • Saves PCB space
  • Improves system reliability

➡️ Gas Discharge Tube - SG4532B400 – 400V, 2KA

https://en.semiware.com/gas-discharge-tubes/sg4532b400

Functions:

  • High current carrying capacity
  • Used with programmable protectors
  • Enhances overall lightning protection level

4️⃣ USB Interface Protection

Frequent plugging and unplugging of USB interfaces poses a high ESD risk.

Recommended Devices:

SR05 TVS Array, 5V, ±20KV, 2pF

https://en.semiware.com/esd-diodes/sr05

  • High ESD rating ±20KV
  • Low capacitance does not affect USB signal
  • SOT-143 small package

Protects the USB controller chip from electrostatic discharge.

🔋 Our XDSL Protection Solutions Offer the Following Advantages

  • Multi-level combined protection design
  • Ultra-low capacitance solution, suitable for high-speed DSL signals
  • High surge withstand capability
  • Complete package options, suitable for high-density PCBs
  • Significant cost-effectiveness
  • Stable delivery time, supporting bulk supply

Because xDSL equipment is constantly connected to public network lines, it is highly susceptible to surge threats. Only a multi-stage combination of gas discharge tubes, TVS diodes, low-capacitance ESD protection, and programmable protectors can truly ensure long-term stable operation of the equipment.

If you are developing or optimizing xDSL communication equipment, please contact us.

https://en.semiware.com/contact