How to select the Zener diode for ESD protection?

Based on the electrical characteristic how to choose zener diode?

---------- Post added at 09:11 ---------- Previous post was at 09:11 ----------

any one pls guide me

**broken link removed**
Review of ESD Approaches -- Zener Diode
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Hope these links may useful to you....

Senthilkumar_rjpm said:

**broken link removed**
Review of ESD Approaches -- Zener Diode
**broken link removed**
Hope these links may useful to you....

Click to expand...

thanks for the reply,
i choosed PESDXS2UT series zener diode ,but as a designer based on that electrical characteristic how can i choose the zener diode.because i m a fresher to this designing ,can know on what basis we are going to choose the zener diode.

you do it on-chip or off-chip?
just make sure the zener breakdown voltge is larger than the maximun operating voltage or singnal amplitude. and can provide effective ESD path when ESD event is happened.
i dont think zener diode is a good candidate for ESD protection device.

Zener diode is works in forward bias mode..you can use as an protector device where the reverce leakage current is there...there is lot of manufacturer are there you can go with data sheet

Regards
Praveen Bhat

its work in both forward and reverse bias mood right?the breakdown voltage should be greater than the supply voltage exactly at what ratio??????any one pls help me

hi Bhavya
when Zener is porward biased, it works as same as ordinary PN junction dione, with approximate voltage drope of 0.7V-1.5V. But when you reverse biase it, when ever the voltage applied across the cathode and anode is reached breakdown voltage of the particular zener, the reverse current starts flowing throgh it(Zener) and maintains that voltage. the break down voltage of the Zener will be specified by the manufacturer.
The relationship between supply voltage and breakdown voltage is also depens on current limiting resister, because, there will be some voltage drop across that resisiter(Rz) too.
we use this resister to protect the zener(to limit the current throgh Zener).

Vin = Vz+Iz*Rz

Bhavya.ab

First off, all ordinary diodes can behave like Zenna diode's in that they all have a reverse break down voltage. However few diodes can sustain the current that usually flows in reverse break down. If you llok at a bog standard signal diode such as the 1N4148 you will see on the data sheet a reverse breakdown voltage around 50Volts. Thus if you are looking at high voltages that are above the Zener voltage range you may need to consider this option.

Secondly some electronic devices (GaS-FETs) can be damaged before an ordinary Zener diode has had time to turn on (often due to high package inductance). In which case you will need to consider specialised devices such as a Transient Voltage Suppression (TVS) diode often called a transorb which uses the Avalanche Effect which can safely shunt off hundreds of amps briefly giving device raitings in excess of 1.5KW of power for a short duration (something a Zener cannot do). However if you are looking at real sustained power to be protected against you will need to consider other devices effectivly in parallel such as gas discharge tubes and rate limiting the rise time to the device by appropriate circuitry.

Thus to give you more solid advice we need to know a little bit more about your application.

praveenlb said:

Zener diode is works in forward bias mode..you can use as an protector device where the reverce leakage current is there...there is lot of manufacturer are there you can go with data sheet

Click to expand...

Bhavya,

If zenner is placed at a node containing resistive divider, take care concerning diode BIAS current.
If you polarise the zenner with a current much bellow than specified value, zenner voltage will decrease under nominal value !!

I suffered with this problem protecting an AC line measurement input circuitry.

+++

hi andre_teprom

we are using zener diode near to connector side for the ESD protection,

Bhavya.ab said:

thanks for the reply,
i choosed PESDXS2UT series zener diode ,but as a designer based on that electrical characteristic how can i choose the zener diode.because i m a fresher to this designing ,can know on what basis we are going to choose the zener diode.

Click to expand...

**broken link removed**
(Zener Diodes - Some Interesting Characteristics)
it may usefull to u...

---------- Post added at 16:32 ---------- Previous post was at 16:28 ----------

Bhavya.ab said:

hi andre_teprom

we are using zener diode near to connector side for the ESD protection,

Click to expand...

Can u provide bit more about your application?

Be careful with zenner diodes ; the switching may be too slow. ; the damage might be done already.
Use transorbs and or MOVs that will switch on fast.

u need characteristics !!