Hi everyone, I'm trying to understand the difference between a TVS diode and an ESD suppressor but honestly I'm having a bit of trouble because on some application notes online it says that they are the same thing... while on others there are separate categories

From what I understand, the main differences are:
----------------Diodes TVS:--------------
- Silicon avalanche diodes
- low capacitance, fast response time
- protect both power lines and high-speed data lines well
- surge energy rating low-medium-high

----------------Suppressor ESD:--------
- polymer structure
- low capacitance, fast response time (like TVS diodes)
- surge energy rating low


In concrete terms, in practice, if I find myself on the LittleFuse website, for example, when should I opt for one and how much for another?
Can you please give examples where you preferred one over the other?
Perhaps with today's technology, a TVS diode does exactly the same thing as an ESD protector?

It's a theoretical question, I don't have a practical example to give... maybe you tell me one and we can make it up just to understand the difference well

 

Both diodes are kinds of zener diodes.

The typical TVS diode (or TRANSZORB (TM)) is designed to protect power supply lines from overvoltage transients. Depending on the mechanical size of the diode they are able to absorb some kW(!) of power for a duration of some 100 us. This is usually enough to trip a fuse in front of the TVS and therefore to protect the circuit behind it. They react on pulses with rise times below 10 us. These diodes come in package sizes of 6 mm * 8 mm for a 3 kW type.

An ESD pulse is a totally different kind of pulse. It has rise time of a few ns, and a duration of maybe up to 100 ns and voltages of some kV but a low energy. Therefore these diodes are designed to withstand and absorb extremly fast transients especially on data lines but the don't need to absorb so much energy. Therefore they are packaged in small, low inductance housings and they can never ever withstand a pulse a typical TVS diode is designed for.

 

Both diodes are kinds of zener diodes.

The typical TVS diode (or TRANSZORB (TM)) is designed to protect power supply lines from overvoltage transients. Depending on the mechanical size of the diode they are able to absorb some kW(!) of power for a duration of some 100 us. This is usually enough to trip a fuse in front of the TVS and therefore to protect the circuit behind it. They react on pulses with rise times below 10 us. These diodes come in package sizes of 6 mm * 8 mm for a 3 kW type.

An ESD pulse is a totally different kind of pulse. It has rise time of a few ns, and a duration of maybe up to 100 ns and voltages of some kV but a low energy. Therefore these diodes are designed to withstand and absorb extremly fast transients especially on data lines but the don't need to absorb so much energy. Therefore they are packaged in small, low inductance housings and they can never ever withstand a pulse a typical TVS diode is designed for.

Thank you very much for your reply. I’d like to take this opportunity to ask where "varistors" fit in between TVS and ESD .. I’m a bit confused about them too.

 

Varistors generally have a much higher capacitance, some 100 pF to some nF. They are also used for protecting power supply lines. For data lines their capacitance is far too high. Quite often varistors are used as a coarse protection device in front of a TVS diode. Also the V/I characteristics are not as flat as those of a TVS diode. You should compare some data sheets.

ESD suppressor diodes are usually used to protect data lines (e. g. USB) against damage by ESD discharge.

 

Varistors, as mentioned above, are significantly slower than silicon based suppressors.
But on the other hand, they have higher energy clamping capabilities per unit of volume, and are inherently bidirectional.
Thus, they are mostly used to protect circuits connected to the AC power line.

A superior suppression strategy uses several different cascaded devices.