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ADS8688:Failure of the ADS8688 chip. the answer is the same non-invalid data 000098D000, 0000B1A100, 000031A100 from the channels.

Alexy Kozar
Prodigy 20 points
Part Number: ADS8688

Hello. When working with an ADS8688 microcircuit, behavior that I did not understand was revealed. The microcircuit is configured for continuous scanning. All 9 channels work correctly, but something happens with the chip, something happens, perhaps because of the interference, and it starts to ignore the measurement of signals at the inputs and respond with the same data:
Channels ch0-ch3, ch6,7 correspond 98D0;
Channels ch3-ch5 meet B1A1;
AUX channel respond 31A1;
To get out of this state helps only the removal of power.
Has anyone come across such a problem, and what solution can there be? thank
___________________________________
Sorry for English, I used google translator

  • 0
    TI__Mastermind 24940 points
    Hello,

    Would you describe what you mean by intereference? Are you aware of any noise entering the device that you suspect is causing this?
    Would you describe any behavior you see before the channels stop responding? for example, do you see a trascient in the digital communications line? a glitch, a brown out effect, where the device is not fully powered but also not fully powered down?

    Trying to understand in more detail what could be happening
    Cynthia
  • 0 in reply to Cynthia
    Prodigy 20 points
    Especially I do not create interference and do not watch them, the situation happens arbitrarily, I can not repeat it forcibly.
    The microcircuit has a DNC pin. Could you explain why it is needed, and what will happen if you connect it to ground or power?
  • 0 in reply to Alexy Kozar
    TI__Mastermind 24940 points
    I understand. When the issue occurs, is there any other odd responses or behavors else where in your circuit?
    Also, do the channels also get latched to the values you mentioned (Channels ch0-ch3, ch6,7 correspond 98D0; Channels ch3-ch5 meet B1A1; AUX channel respond 31A1;), no matter what the input was at the time? In other words, do the outputs latch at the input value the moment the issue occurs, or is the input at another voltage value than the one outputed?

    As you mentioned pin 35 is a Do Not Connect pin, the description states that that the node cannot be connected to anything and left to be floating. From this I infer that there possibly is an internal connection in this pin, and connecting it to anything could cause damage or malfunction. I would suggest to leave the pin floating as the datasheet states.

    Regards, Cynthia