ESD diode selection

Hari Thazhe Oyyoth

Hi ,

May I know how to decide whether an application requires uni directional ESD diode or Bidirectional ESD diode.

From an application note I read a statement ,it states that "Unidirectional
avalanche and diode arrays should only be used in systems
where the difference in the voltage potential of the ground
references is small."

Can anyone please explain what the above statement means exactly.

Regards

Hari

over 9 years ago

0 Guy Yater over 9 years ago

TI__Genius 12190 points

It is talking about having more than one ground. I know that for a unidirectional, the voltage on the protection pin cannot drop below 0-V, to prevent the diode from breaking down. For an avalanche diode, the voltage should not exceed the breakdown of the Zener voltage, and a diode array can be bi-directional or unidirectional depending on the structure of the array. In all cases, the voltages allowed on the protection pin are "usually" 0V-6V for an avalanche or unidirectional, and -7V to 7V on the bi-directionals.

Regards,

0 Hari Thazhe Oyyoth over 9 years ago in reply to Guy Yater

Intellectual 380 points

Hi Guy Yater,

Thank you vey much for your time and concern.
Could you please explain the concept of "more than one ground" taking some example ,let it be CAN bus.

Thanks&Regards
Hari

0 Guy Yater over 9 years ago in reply to Hari Thazhe Oyyoth

TI__Genius 12190 points

Hi Hari,

It is common to use separate ground planes for digital and analog circuits that have separate grounds. There are many documents available describing this. For instance, I recommend reading:

Grounding in mixed-signal systems demystified, Part 1

Grounding in mixed-signal systems demystified, Part 2

Regards,

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ESD diode selection