What is TVS DIDOE

TVS diode, also known as transient suppression diode, transil, transorb or thyrector, is an electronic component used to protect electronic devices from voltage spikes induced on connecting wires

TVS diodes are used in ICs (integrated circuits) to protect against overvoltage and the effects of arcs, EFT (Electrical Fast Transients), ESD (Electrostatic Discharge), inductive load switching, and even lightning strikes.

The characteristics of TVS diodes:

* Leakage current: the amount of current conducted when voltage applied is below the maximum reverse standoff voltage.

* Maximum reverse standoff voltage: the voltage below which no significant conduction occurs.

* Breakdown voltage: the voltage at which some specified and significant conduction occurs.

* Clamping voltage: the voltage at which the device will conduct its fully rated current (hundreds to thousands of amperes).

* Parasitic capacitance: The nonconducting diode behaves like a capacitor, which can distort and corrupt high-speed signals. Lower capacitance is generally preferred.

* Parasitic inductance: Because the actual over voltage switching is so fast, the package inductance is the limiting factor for response speed.

* Amount of energy it can absorb: Because the transients are so brief, all of the energy is initially stored internally as heat; a heat sink only affects the time to cool down afterwards. Thus, a high-energy TVS must be physically large. If this capacity is too small, the over voltage will possibly destroy the device and leave the circuit unprotected

 

The working principle of TVS diode

When an abnormal overvoltage occurs in the circuit and reaches the breakdown voltage of the TVS diode, the TVS diode quickly transitions from a high resistance state to a low resistance state, releasing the instantaneous overcurrent caused by the abnormal overvoltage to ground, while clamping the abnormal overvoltage at a lower level, thus protecting the subsequent circuit from damage caused by the abnormal overvoltage. After the abnormal overvoltage disappears, the resistance of the transient suppression TVS diode returns to a high resistance state.

The volt ampere characteristic curve and related parameters of the TVS transient suppression diode are shown in Figure 1. The volt ampere characteristic curve of the bidirectional TVS diode series products has opposite polarity in the first quadrant and similar characteristics in the third quadrant, as shown in Figure 2. When the TVS is reverse biased, it has two operating modes: standby (high impedance) or clamp (relatively low impedance), as shown in the third quadrant of Figure 2.

In standby mode, the current flowing through the TVS is called standby current (IR) or leakage current, and the magnitude of this current varies with the junction temperature of the TVS. In the volt ampere characteristic curve of TVS, the transition from high impedance (standby) to low impedance (clamp) is the beginning of avalanche breakdown. When TVS is completely avalanche broken down, it will instantly convert high voltage into a large current flowing through its body and maintain a relatively low clamp voltage at both ends of the PN junction.

Unidirectional TVS volt-ampere characteristic curve (1)

 

Volt-ampere characteristic curve of bidirectional TVS (2)

 

 

Types of TVS DIODE

 

Classified by polarity:

Unidirectional TVS diode

Characteristics: Unipolar TVS diodes can only withstand overvoltage in one direction, suitable for DC circuits or circuits that only require unidirectional protection. Its characteristic curve is similar to that of a Zener diode. When the voltage exceeds the breakdown voltage, the diode conducts in reverse and releases current.

Application: Commonly used for overvoltage protection in DC power supply circuits, such as DC power lines, low-voltage electronic devices, etc.

 

Bidirectional TVS diode

Features: Bipolar TVS diodes can suppress overvoltage in both positive and negative directions, making them suitable for AC circuits and bidirectional voltage fluctuations. It can be

Symmetrical protection against transient overvoltage is provided in two directions, making it common in AC power or signal lines.

Application: Commonly used for AC power cords, data communication interfaces, and other circuits with positive and negative voltage changes

 

Classified by packaging

SMD TVS diode

Features: Surface mount technology (SMD) is used for surface mount TVS diodes, which are small in size, low in power consumption, and suitable for integration into compact circuit board designs. Usually packaged in forms such as DO-214AA (SMA), DO-214AB (SMB), etc.

 

Application: Widely used in miniaturized and integrated circuits such as consumer electronic devices, mobile devices, communication devices, etc.

Through hole TVS diode

Features: Direct insertion TVS diodes are commonly used in high-power circuits, capable of withstanding higher currents and energy. They are commonly packaged as D0-201, DO-15, etc

Application: Suitable for scenarios that require high power and high wave tolerance, such as power equipment, industrial control systems, etc.

Classify by application scenario

Universal TVS diode

Features: Universal TVS diodes are suitable for transient overvoltage protection in most ordinary circuits, with a wide operating voltage range and the ability to cope with general surge currents.

Application: Widely used in consumer electronics, power protection, low-power devices and other fields.

Specialized TVS diode

Features: Specialized TVS diodes are designed for specific applications, with higher response speed, lower capacitance, or higher power tolerance, suitable for specific signal lines and interface protection

Common categories

Low capacitance TVS diode: designed specifically for high-speed data communication lines, with an extremely low capacitance value, usually below 1pF, suitable for high-speed interface protection such as USB 3.0, HDMI, SATA, etc.

High power TVS diode: designed to handle high-energy surge events, commonly used for industrial equipment and power surge protection, capable of withstanding higher pulse currents.

ESD Protection TVS Diode

Features: Specially designed for electrostatic discharge (ESD) protection, with extremely low clamping voltage and fast response capability, capable of instantly clamping ESD peak voltage within a safe range. Usually packaged very small, suitable for interface protection that is sensitive to static electricity.

Application: Widely used in devices that are susceptible to ESD, such as USB interfaces, HDMI interfaces, audio interfaces, touch screens, buttons, etc.

High Speed TVS Diode

Features: Designed for high-frequency applications, it has low capacitance and low loss characteristics, and can provide transient voltage protection without affecting signal integrity.

Application: Commonly used in high-speed communication equipment, such as Ethernet, fiber optic communication, HDMI and other high-speed signal transmission lines

Classified by power level

Low power TVS diode

Features: Low power TVS diodes can withstand low surge currents, typically between tens of watts and hundreds of watts, and are suitable for overvoltage protection in low-power circuits.

Application: Suitable for transient voltage suppression in small electronic devices and precision circuits, such as consumer electronics, sensors, embedded systems, etc

 

Medium power TVS diode

Characteristics: Medium power TVS diodes have a high power tolerance, generally between 500W and 5kW, and can cope with moderate voltage transients, making them suitable for slightly higher power application scenarios.

Application: Widely used in communication equipment, power circuits, industrial electronic devices, etc.

 

High power TVS diode

Features: High power TVS diodes can withstand higher transient power, usually above 5KW, suitable for high-energy surge protection. They can protect circuits under extreme voltage conditions and prevent equipment damage.

Application: Suitable for overvoltage protection of power lines, high-power electronic devices, industrial control systems, and energy systems (such as solar inverters).

 

According to the requirements of the circuit, TVS diodes can be selected based on their polarity, packaging form, application scenarios, and power levels. For circuits with high-speed communication interfaces and low capacitance requirements, low capacitance or high-frequency TVS diodes are the best choice; For high-energy surge protection, high-power TVS diodes are more suitable. Understanding these classifications helps designers choose the most suitable TVS diode to ensure the safety and stability of the circuit

 

How to order of TVS DIODE

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Engineer team to do “cross to”

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Simply send RFQ to lily@topdiode.com for quote of TVS DIODE .

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