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DRA821U: ESD immunity

Tsurumoto
Genius 15254 points
Part Number: DRA821U
Other Parts Discussed in Thread: DRA821, AM3352

Hi

What is the ESD immunity of the DRA821?

The DRA821 seems to have low ESD immunity.

(For example, that's about half the AM3352.)

What factors affect ESD immunity?

Thanks and Best regards,

Tsurumoto.

  • +1
    TI__Guru 54342 points

    Hello Tsurumoto-san,

    It may just be the conditions that the different parts were tested in.  The value in the DRA821 datasheet matches J6, and is the standard methodology used by Jacinto processors and meets auto requirements.

    Even the AM335x device has this footnote:

    Regards,

    Kyle

  • 0 in reply to kcastille
    TI__Genius 15254 points

    Hi Kyle

    I compared between DRA71x and AM570x. Both are J6Entry model.

    DRA71x:

    AM570x:

    I guess the test condition for DRA71x is Automotive base, and it for AM570x is Indy (?) base.

    However, the number of ESD for both are same.

    I believe that there are some other factor which affect to it.

    Thanks and Best regards,

    Tsurumoto.

  • +1 in reply to Tsurumoto
    TI__Guru 54342 points

    Right since J7Entry is tested in 1 way, both data sheets reflect the same value.  For arbitrary reasons, the AM335x device was tested to a higher (unnecessary) level as stated in its own footnotes.

    This doesn't necessarily mean there is a difference in their performance (though this is not guaranteed as per the spec)

    Regards,

    Kyle

  • 0 in reply to kcastille
    TI__Genius 15254 points

    Hi Kyle

    I'm very sorry, but I'm confusing now...

    I pasted J6Entry again to the below.

    AM570x also has the footnote which is same with the one for AM335x.

    I mean, lock like that the test condition are different between DRA71x and AM570x, but ESP value for both are the same.

  • 0 in reply to Tsurumoto
    TI__Genius 15254 points

    Hi

    I really need your help for this questions soon...

  • 0 in reply to Tsurumoto
    TI__Genius 15254 points

    Hi

    Could you please give us your replay?

  • +1 in reply to Tsurumoto
    TI__Guru 54342 points

    Tsurumoto-san,

    The test conditions and thus the reported ESD ratings for the DRA71x and AM570x are the same.  

    The footnote has nothing to do with the test conditions - the footnote is saying ... "JEDEC standard says 500-V HMB is safe".  Considering we're 2x higher value on HBM (1000-V) that implies we have lots of margin to a safe test condition for HBM.  CDM of 250 meets the JEDEC safe recommendation.

    Regards,

    Kyle

  • 0 in reply to kcastille
    TI__Genius 15254 points

    Hi Kyle

    Where customer can refer the ESD test condition for DRA821 to?

  • +1 in reply to Tsurumoto
    TI__Guru 54342 points

    Tsurumoto-san,

    The test conditions are as per the standard: 

    HBM => ANSI/ESDA/JEDEC JS-001(1)

    CDM => per JEDEC specification JESD22-C101

    Regards,

    Kyle

  • 0 in reply to kcastille
    TI__Genius 15254 points

    Hi Kyle

    OK, therefore, the test conditions for both DRA821 and AM335x are same.

    HBM => ANSI/ESDA/JEDEC JS-001(1)

    CDM => per JEDEC specification JESD22-C101

    So, I cannot understand well what does "the conditions that the different parts were tested in" mean which you commented at 1st your reply.

    kcastille said:
    It may just be the conditions that the different parts were tested in.  The value in the DRA821 datasheet matches J6, and is the standard methodology used by Jacinto processors and meets auto requirements.

    Why ESD were different between DRA821 and AM335x?

    DRA821:

    AMM335x:

  • +1 in reply to Tsurumoto
    TI__Guru 54342 points

    Tsurumoto-san,

    I meant that the test mechanism is the same as described by the ANSI/JEDEC standards.  The tables show the difference in the stress voltages applied.  Jacinto/Automotive has always used the 1000/250 V levels.  I don't know why Am335x tested higher.  I really don't think it matters considering 500/250 is deemed safe in the industry.

    Regards,

    Kyle