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DAC8580: Question about DAC8580 Data-Sheet

Part Number: DAC8580

1.

By DAC8580 Data-Sheet

P13, [During power up, all digital inputs and the reference input should be kept at zero volts.   If any pin is brought high before the power supplies, overvoltage protection circuitry turns on.]

About item mentioned above, Which is target of power-pin?

DVvdd (+3.3V) AVdd (+5V) AVss (-5V) all?
DVdd (+3.3V) only?

2.

In the case of our products (Industrial control-board)

1st step:   DVdd (+3.3V)  go from 0V to +3.3V

2nd step:  At nearly same-time of 1st step, Digital input (SDIN SDCLK OSR1 OSR2 ・・・)   go to +3.3V, by 25kohm pull-up.

3rd step:  After 50msec delay, AVdd (+5V) AVss (-5V)  go to +5V, -5V.

 

Is there something wrong?

Overvoltage protection circuit turn-on?

  • Hello,

    Thank you for your query. This part is NOT RECOMMENDED FOR NEW DESIGNS (NRND). So, if you are considering it for new designs, choose another part instead. If you can provide your requirements, I can suggest an appropriate part.

    In case it's an existing design, your power supply sequencing looks fine to me.

    Regards,

    Uttam Sahu

    Applications Engineer, Precision DAC

  • Hello Uttam 

    Thanks for your kindness. 

    This case is an existing design.  Please confirm attached file.  (power sequence_20191120.doc)

    Regards
    Isao Nishitanipower sequence_20191120.docx
    Uttam Sahu said:

    Hello,

    Thank you for your query. This part is NOT RECOMMENDED FOR NEW DESIGNS (NRND). So, if you are considering it for new designs, choose another part instead. If you can provide your requirements, I can suggest an appropriate part.

    In case it's an existing design, your power supply sequencing looks fine to me.

    Regards,

    Uttam Sahu

    Applications Engineer, Precision DAC

    Uttam Sahu said:

    Hello,

    Thank you for your query. This part is NOT RECOMMENDED FOR NEW DESIGNS (NRND). So, if you are considering it for new designs, choose another part instead. If you can provide your requirements, I can suggest an appropriate part.

    In case it's an existing design, your power supply sequencing looks fine to me.

    Regards,

    Uttam Sahu

    Applications Engineer, Precision DAC

  • Hello Uttam

    Could you confirm my previous-mail with "power sequence_20191120.doc" ?

    I am looking forward to your reply.

    Thanks, Regards

    Isao Nishitani

  • Hello Uttam

    Anything update?    Under investigation?

    Isao Nishitani

  • Hello, Uttam

    By end f this week, I want get your comment.

    Thanks, Regards

    Isao Nishitani

  • Hi Isao-san,

    The power sequencing looks fine to me. Are you facing any problem currently?

    Regards,

    Uttam

  • Hello, Uttam

    Good days. 

    In the case of 2 failure of our products, DAC DAC8580 were destroyed.(Output signal wave is not regular.)

    We are researching for cause of destruction, now.

     

    We were concerned about power-sequence.

    However, your reply is that “The power sequencing looks fine to me.”

    We will consider the other cause of problem.

     

    Thanks, Regards

    Isao Nishitani

  • Hello, Uttam

    Good days. 

    Could you have any comment ?

    Could you have any advice about DAC DAC8580 failure ?

    Could you have any proposal about schematic ? (Schematic had been sent on previous-mail)

    Thanks, Regards

    Isao Nishitani

     

     

  • Under study?    Any updates?

  • Hi Uttam

    Good morning. Good day.

    Your comment is only “The power sequencing looks fine to me.”

    Could you supply more detail information?

    What reason is your judgement “The power sequencing looks fine to me.”?

    Regards.

    Isao Nishitani

  • Hi Isao,

    From the schematics, I was unable to find out any root cause for the failure. Do you have the sequence of events that caused the failure or is it happening every time?

    Sorry for the delay in response due to the year-end work load.

    Regards,

    Uttam

  • Hi Uttam

     

    While end-user use this board, failure happened.

    User claim.     2-case.

    Failure-board come back to us.

    We checked and knew that Output signal(DAC8580) wave is not regular.

    Therefore, we do not know the sequence that caused the failure.

     

    We continue analyzing root cause.

    Not only power-sequence but also other cause (i.e. GND-noise by regulator switching.)

    I appreciate your kindness.  

    Thank you a lot.

    Regards,

    Isao Nishitani

  • Hi Isao,

    As there are many modes in which the device might have failed, it is difficult to guess from my end just by looking at the schematics. Good that you are analyzing the root cause. Please let me know if you find any other clue and I can support analyzing that. 

    Due to the year-end vacations, please expect some slowness in my responses.

    Regards,

    Uttam

  • Hi Uttam

    Thank you, a lot.

    If I find other clue, I will contact again.

    Regards,

    Isao Nishitani