TVS diodes and Zener diodes are both nonlinear components and can break down and conduct under specific voltage conditions, but their design goals, operating characteristics, and application scenarios are significantly different. The main differences are as follows:

1.Design Goals and Application

TVS diode:
Designed to protect circuits from transient overvoltages (such as lightning strikes, electromagnetic pulses, electrostatic discharges, etc.). TVS diodes are characterized by extremely fast response speeds and the ability to handle high-energy transient voltages within nanoseconds. Its main application is overvoltage protection for sensitive components in circuits (such as microprocessors, memories, interface circuits, etc.).

Zener diode:
Designed for voltage stabilization, it is often used to provide a stable voltage for circuits. Zener diodes operate under reverse bias and maintain a stable voltage output when the reverse voltage exceeds its breakdown voltage. It is often used in stabilized power supplies, reference voltage sources, and other occasions.

2.Working Principle

TVS Diode:
The working principle of TVS diode is based on its fast response to transient overvoltage. When a transient high voltage appears, the TVS diode breaks down and conducts almost immediately, absorbing or shunting the overvoltage through its low impedance path to prevent the overvoltage from damaging the circuit. It is mainly concerned with rapid changes in voltage (such as voltage pulses).

Zener Diode:
Zener diode works under reverse bias. The principle is that when the reverse voltage exceeds its Zener voltage, it will start to work stably and maintain a fixed voltage value. It is usually used to provide voltage regulation or voltage reference. Zener diode performs well in voltage regulation and voltage control, but its response speed is slow and it is not suitable for fast overvoltage protection.

3.Response Speed

TVS diode:
The response speed is very fast, usually in nanoseconds, and can suppress transient voltage in a very short time. This makes it effective in preventing damage to circuits caused by transient voltages such as lightning strikes, electromagnetic interference (EMI), and electrostatic discharge (ESD).

Zener diode:
The response speed is relatively slow, usually in milliseconds. It is more used for voltage regulation rather than transient voltage protection, so it is not suitable for fast overvoltage suppression.

4.Breakdown Voltage and Current

TVS diode:
TVS diodes usually have a high breakdown voltage and can withstand large transient currents. They are designed to handle high-power transient voltage waveforms, usually withstand currents of up to several hundred amperes (or even higher), and can absorb large amounts of energy in a very short time.

Zener diode:
Zener diodes have a lower breakdown voltage, usually ranging from tens of volts to several hundred volts, and withstand smaller currents. They are mainly used to provide a stable voltage rather than withstand transient overvoltages with large currents. Therefore, Zener diodes are not suitable for high-energy transient overvoltage protection.

5.Applications

TVS diode:
Mainly used for transient voltage protection, such as power input, communication interface, automotive electronics, computer interface, industrial control, etc. TVS diode is used to prevent voltage spikes caused by lightning, electromagnetic pulse (EMP), electrostatic discharge (ESD), etc. from damaging the circuit.

Zener diode:
Mainly used for voltage stabilization applications, such as voltage regulators, reference voltage sources, and voltage regulation in power circuits. Zener diodes can provide stable voltage in low-power applications and are usually used for voltage stabilization and voltage reduction.

6.Device Structure

TVS diode:
The structure of TVS diode is usually designed to be rough so as to withstand the impact of transient voltage and have a large current carrying capacity. Common TVS diodes are bidirectional and unidirectional.

Zener diode:
The structure of Zener diode is relatively simple and is usually designed as a unidirectional diode. It ensures the stability of its breakdown voltage by selecting the appropriate doping concentration and structure.

In short, TVS diodes are specifically designed to cope with and suppress transient voltage pulses, while Zener diodes are used to provide stable voltage. The two are significantly different in performance and application.

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