Sunday 4 June 2023

What is TVS diode ?, How to select the TVS diode ?

 A TVS (Transient Voltage Suppression) diode is a type of diode that is designed to protect electronic circuits from voltage spikes or transients. It acts as a voltage clamping device, quickly diverting excessive voltage away from sensitive components and preventing damage caused by overvoltage events.


When a voltage spike occurs, such as from electrostatic discharge (ESD), lightning strikes, or switching transients, the TVS diode responds by conducting excessive current and limiting the voltage to a safe level. Once the transient event is over, the TVS diode returns to its high-resistance state, allowing normal operation of the circuit.







We can use the TVS Diode as following types different purposes ,


1.Surge protector diodes


These are generally called TVS (Transient Voltage Suppressor), and are used as a voltage clamping surge protector.  The clamping voltage is expressed as VCL.

This diode is categorized as a power semiconductor and is made to absorb a large amount of energy for a short period in order to ensure a low operating resistance and high current rating. The surge voltage Vp is absorbed and reduces it up until VCL.





2.Voltage regulator diodes

By running a slight current through the Zener diode, it is uses the voltage between K and A as a reference voltage.

This diode is generally not made for large current flow, and is categorized as a small-signal semiconductor.

When Vi>VZ, even if Vi and IZ change, VZ becomes an almost constant value.




To select the appropriate TVS diode for a specific application, you need to consider the following factors:


Voltage Rating: 

Choose a TVS diode with a voltage rating higher than the maximum expected voltage that the circuit needs protection against. The voltage rating should account for potential transients and voltage surges that may occur in the system.


Peak Pulse Power (Ppp): 

The TVS diode should have a peak pulse power rating sufficient to handle the energy of the transient event. This rating indicates the maximum power that the TVS diode can dissipate without damage.


Clamping Voltage: 

The clamping voltage is the voltage at which the TVS diode begins to conduct and limit the voltage. Select a TVS diode with a clamping voltage lower than the maximum acceptable voltage for the protected circuit.



Response Time:

 Consider the response time of the TVS diode, which is the time it takes for the diode to respond and start conducting after the transient event occurs. A faster response time provides better protection for sensitive components.


Package and Mounting:

 Choose a TVS diode package that is suitable for your circuit and compatible with the mounting options available. Common TVS diode packages include SOD, SMC, SMA, or SMB.


Leakage Current: 

Take into account the leakage current of the TVS diode, which is the current that flows through the diode when it is in its off-state. Ensure that the leakage current is within acceptable limits for your application.


Environmental Conditions: 

Consider the operating temperature range, humidity, and other environmental factors to ensure the TVS diode can withstand the conditions it will be exposed to.



It is recommended to consult the datasheets and specifications provided by the TVS diode manufacturers to determine the most suitable device for your specific application. Additionally, it can be beneficial to consult with experienced engineers or seek expert advice to ensure the proper selection and implementation of TVS diodes for effective circuit protection.




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