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DAC121S101QML-SP: Digital IO powered without power supply

Part Number: DAC121S101QML-SP

Hello,

Could someone say if the DAC121S101QML-SP can have its digital inputs with a dc voltage (3.3V) present without power supply on Va pin?

Is there ESD protections on these pins? If yes, what is the maximum current for ESD diodes?

Thanks

  • Hello Matthieu,

    The DAC121S101QML-SP does have ESD diodes.  The max current is 10 mA and the max voltage is Va + 0.3V.

    Violating either can impact the life of the part.   Restricting the curren to below 10 mA but having the voltage on a pin greater than Va + 0.3V might not cause immediate damage to the part but could impact the life of the part.

  • Hello Kirby,

    We have made some measurements on a DAC121S101QML-SP and we have found that there is ESD diodes to GND on each pins but only ESD diode to VA on the VOUT pin.
    Could you confirm (or not) that there is no ESD diode between SYNC#, SCLK and DIN to VA, please?

    Thanks
  • Hi Matthieu,

    The part has a complex ESD protection circuit.   You will not see a diode between the input pins and Va.   The diode is a snapback diode and does not turn on until the input voltage goes above 5.5 V.

  • Hi Kirby,

    Thanks for your answer. So I have again two questions :

    - In this case, why in the datasheet with cannot have a voltage above Va + 0.3 (and not 5.5V) on digital IO?

    - What is the inpact of having digital IO at 3.3V without Va powered. If I'm right in this case ESD diode will not turn ON and the DAC will not be stressed?

    Thanks

  • Hi Matthieu,

    That is an error in the datasheet. The abs max for the input pins should be 6.5 V. This will be updated in the next rev. of the datasheet.

    By the way, the structure of the input pin is shown at the bottom of page 4, which matches what you saw.