Avalanche diodes are semiconductor components designed to operate without damage in the reverse breakdown region. Although they behave similarly to Zener diodes, their basic mechanism and protection against high voltages make them important in circuits subject to transient voltages, overvoltages and transients.
This guide explains what avalanche diodes are, how they work, the main characteristics of avalanche diodes and where they are used. It also tells you where to find reliable avalanche diodes and other protection components from DRex Electronics.
⚙️ What is an Avalanche Diode?
An avalanche diode is a silicon diode designed to turn on when the voltage exceeds a certain threshold, called the avalanche breakdown voltage. Unlike conventional diodes, which can fail in this situation, avalanche diodes are designed to resist and control the failure process.
Key features:
- Operates at the reverse voltage when the breakdown voltage is reached.
- Capable of passing high reverse currents without damage.
- Often used in voltage clamps, surge suppressors and suppression circuits.
Do you want to protect your circuits against transient voltages? Check out DRex Electronics ‘ full range of avalanche diodes and protection components.
How do avalanche diodes work?
Avalanche protection diodes work due to the avalanche effect:
- When the reverse voltage increases above a certain level, the electric field inside the diode is amplified , resulting in the release of electrons by pulsed ionisation.
- These released electrons collide with atoms and release more electrons, causing an avalanche effect.
- The diode goes into a fault mode allowing high currents to flow, but it is not damaged because it is designed to cope with this situation.
⚠️ IMPORTANT: Avalanche diodes should be used in conjunction with a current-limiting resistor or circuit to avoid thermal overload.
📊 Key Specifications of Avalanche Diodes
| Specification | Description |
|---|---|
| Breakdown Voltage (Vz) | Voltage at which avalanche conduction starts |
| Clamping Voltage | Maximum voltage allowed during conduction |
| Peak Pulse Current (Ipp) | Max surge current the diode can withstand |
| Reverse Leakage Current | Current flow under normal reverse voltage |
| Response Time | Time to respond to a transient (often nanoseconds) |
| Power Dissipation | Maximum power the diode can handle during a surge |
🧰 Avalanche Diode vs. Zener Diode
| Feature | Avalanche Diode | Zener Diode |
|---|---|---|
| Breakdown Mechanism | Avalanche effect | Quantum tunneling (Zener effect) |
| Typical Voltage Range | Higher (above 5V) | Lower (under 5V) |
| Application Focus | High-voltage surge protection | Voltage reference, regulation |
| Current Handling | Handles higher surge currents | Lower current capability |
👉 Read our Zener Diodes Guide for more on low-voltage regulation components.
📦 Applications of Avalanche Diodes
✅ 1. Surge Protection
Avalanche diodes absorb overvoltage transients in power lines or signal interfaces to protect sensitive electronics.
Use Case:
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AC power supplies
-
Battery management systems
-
Microcontroller inputs
✅ 2. Inductive Load Protection
When switching off inductive loads (motors, relays), avalanche diodes are used to clamp voltage spikes generated by back-EMF.
Use Case:
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Relay driver circuits
-
Automotive electronics
-
Motor control systems
✅ 3. Snubber Circuits
Paired with resistors or capacitors, avalanche diodes help suppress high-speed voltage spikes in switching power supplies (SMPS).
✅ 4. Communication Line Protection
In long communication lines, avalanche diodes act as voltage clamps to protect transceivers from static discharge or surge.
Use Case:
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RS-485, CAN bus
-
Ethernet or USB protection
👉 Need protection for communication lines? Browse our TVS diodes, avalanche, and ESD suppressors.
🛠️ Avalanche diode design tips.
- Always add a series resistor to limit the current during avalanche conduction.
- Match the terminal voltage to the maximum allowable voltage of the circuit to be protected.
- Place the diode as close as possible to the transient source or sensitive load.
- Avalanche diodes for inductive loads may be used in parallel with relays or motor coils.
Where can I buy avalanche diodes?
They are available fromDRexElectronics:
- Avalanche diodes for surge protection and inductive protection.
- DO-41, DO-15 and SMD packages to meet different design requirements.
- ✅ Power ratings from 400 W to 5 kW+ for high energy protection.
- ✅ Trusted brands .
- ✅ Support for OEMs, repair services and industrial design teams.
Support for OEMs , repair service providers and industrial design teams.
Conclusions
Avalanche diodes are an important means of protecting sensitive electronic components against high voltage transients, inductive spikes and overvoltages. Their ability to safely perform reverse conduction makes them ideal for surge protection, motor drive protection and high-speed switch applications.
🔧 Want to increase the reliability of your circuit?
Visit DRex Electronics, your expert supplier of vacuum diodes, TVS protection components and high-quality semiconductor solutions.
