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What Is The Best Testing Way to Screen EOS Damaged Diodes?

08/07/2012 11:33 AM

Hellow CR4 guys:

What is the best way to screen EOS damaged diodes?.

I have a lot with diodes that has EOS damaged diodes. I have not more diodes and I would like to know if somebody has a great idea how to screen them.

Best regards!

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#1

Re: What Is The Best Testing Way to Screen EOS Damaged Diodes?

08/07/2012 2:02 PM
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#2

Re: What Is The Best Testing Way to Screen EOS Damaged Diodes?

08/07/2012 2:07 PM

A few ideas. First, for electrical overstress components I would look for any burnt, discolored markings, or out right damaged components. Second what is left you could use a multimeter set in diode test or on low resistive scale and test them. By looking for open or shorted then discarding them.

The diode test will pass a voltage in one direction but not the other. So do not confuse this as a bad one.

Third way if you have a oscilloscope you could build a simple V/I curve tracer. That would give you a visual of good versus bad.

Charles

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#3

Re: What Is The Best Testing Way to Screen EOS Damaged Diodes?

08/07/2012 2:59 PM

Great suggestions that has been posted.

Let me increase the difficulty.

When a diode is EOS damaged but is not dead, the diode can work for a period of time that could scape the final electrical test for the final product we handle.

For the case of a dead diode or shorted diode due to EOS, we can screen them out with a multimeter, an I-V curve characterisation or a circuit with a light.

For the case of a damaged diode but not dead, we have experience that in most of the cases with the I-V curve of such wounded diodes shows a difference in the rising curve between 0V and VD.

I am not confident that this procedure will screen all the damaged diodes.

What do you think?

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#8
In reply to #3

Re: What Is The Best Testing Way to Screen EOS Damaged Diodes?

08/08/2012 3:15 AM

It sounds as though major overhaul is needed to the design and operation of the circuit that damages the diodes. Why on earth build and use a 'diode damager'?

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#4

Re: What Is The Best Testing Way to Screen EOS Damaged Diodes?

08/07/2012 5:54 PM

I would regard the EOS failures as a symptom of the process exceeding the component design condition and thus indicative that ALL diodes exposed have been damaged and are thus defective.

If the device is for anything other than a gift card tune or some other item where failure outcome is negligible, then replace the lot.

Don't spend the effort with a sorting process that "might" find the damaged ones. Spend the effort correcting the problem.

Most customer groups will have long memories if you pass on these items and then in a year get heaps of failures. Even if the use is internal to your organisation, other departments will start to bill you for downtime and repair costs and expect free replacement assemblies.

Spend the effort and get it right.

BTW, what else has been exposed to the stress and what are their ratings?

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#5
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Re: What Is The Best Testing Way to Screen EOS Damaged Diodes?

08/07/2012 6:01 PM

I do agree.

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#6

Re: What Is The Best Testing Way to Screen EOS Damaged Diodes?

08/07/2012 11:49 PM

Smash them up with a hammer and then put them through this

Recover the copper, sell it, and buy some good diodes.

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#7

Re: What Is The Best Testing Way to Screen EOS Damaged Diodes?

08/08/2012 1:20 AM

Do a real diode I-V and analysis and determine the A-factor and the other parameters http://www.chalcogen.infim.ro/933_Alfaramawi.pdf

So, a pulse test for breakdown in the forward and reverse direction.

Look up SMU (Source Measure Units) fro Agilent, Keithley and Yokagowa)

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#9

Re: What Is The Best Testing Way to Screen EOS Damaged Diodes?

08/08/2012 3:43 AM

what are they? can you make out the part No's,I have million electronic components and amongst then thousands of diodes, most are obsolete.

Bazzer

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