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DAC8580: AVDD stuck to -0.7V

Alexian Bobo
Prodigy 20 points
Part Number: DAC8580

Hello,

I integrated on my board 6 DAC8580 to generate 40kHz sinusoid signals.

The DACs have to power supply rails -5V on AVSS and +5V on AVDD as required but unfortunately, the positive supply rail is stuck at -0.7V. I removed the 6 DACs and it is working properly at 5.0V.

If I remove the voltage converter and inject the voltage from a laboratory power supply, the 5V seems fine with a 110mA current consumption. If I test my voltage converter with an active load, it works properly under 340mA and after, only reduce the voltage to keep a constant limit current. It is hard to understand why it does not work with all together...

I have 4.7uF decoupling capacitor on every power supply pin, it seemed a little bit high so I removed it and only kept 100nF per pin + other 4.7uF and 10uF on the output pin of the converter but it did not change anything.

Would have someone already encountered such problem with this DAC.

Best regards,

Alexian

  • 0
    TI__Mastermind 31598 points

    Hi Alexian,

    I have not heard of this problem with this DAC.

    Thanks for confirming your power supply should be meeting the current consumption requirements. Can you share your schematic? Is it possible for you to test with only one DAC8580 populated and check if the supply voltage is working as expected? 

    Best,

    Katlynne Jones

  • 0
    Prodigy 20 points

    I found the issue this morning.

    The positive supply rail was generated from a 6V rail himself generated from a 9V rail while the negative supply rail was generated directly from a -9V rail.

    Because of that, the positive supply rail was high about 1.5ms after the negative rail which caused a voltage drop on the positive rail before its activation.

    After that, the chosen LDO generating the +5V rail was stuck in a protection mode from negative voltage on its output.

    To solve the issue, I used the enable/shutdown pins of the +5V and -5V LDO to start them at the same time.

    Thanks for paying attention to my topic !

    Alexian

  • 0 in reply to Alexian Bobo
    TI__Mastermind 31598 points

    Hi Alexian,

    Glad to hear you solved the issue. Please reach out if you have any further questions. 

    Best,

    Katlynne Jones