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DAC80502: Device failure mode and limitation.

shinichi miyano
Intellectual 300 points
Part Number: DAC80502

Hello

This is a question for circuit protection design in case of a failure.
1) According to the data sheet, the absolute rating of the input current to each pin is defined as up to 10mA.
How long can be tolerated if a current about 50mA flows through the OUT pin?

2) In addition, how does DAC behave in above case?

Best Regard

Miyano Shinichi

  • 0
    TI__Guru 53773 points

    Hi Shinichi-san,

    The device has a short circuit current capability of about 30mA.  This is the peak current that the device can sink and source in normal operation.  When you exceed this current, then you might see the output voltage exceed the GND/VDD voltage limitations, which would activate the ESD cells.  Prolonged ESD cell activation can damage these diodes.  Generally, this requires that whatever load you have connected to the device can support a higher voltage than the VDD/GND supplies.  If the current only lasts for a few milliseconds, then I doubt there will be any damage, but it is difficult to provide any exact number.  Ultimately, we do not recommend this case.  Sometimes, a small series resistance and output capacitor can absorb and attenuate current transients.  Would it be possible to implement some protection in this application?

    Thanks,

    Paul

  • 0 in reply to Paul_Frost
    Intellectual 300 points

    Hello Paul

    Thank you for your reply. 

    I generally understand our answer. Let me check one point. 

    >The device has a short circuit current capability of about 30mA.

     ->Does it mean that even if the power supply line with the same voltage as VDD and the OUT pin of DAC are short-circuited due to a board failure, the current can be limited to 30mA?

    Best Regard

    Miyano Shinichi

  • 0 in reply to shinichi miyano
    TI__Guru 53773 points

    Hi Shinichi-san,

    1. If you were to short the output to GND or VDD, you would see typically a max current of 30mA.  This would damage the device as the DAC is the source or sink of the current.  The 10mA should apply to all pins except VOUT, VDD, and GND.

    The voltage limitations in the abs. max. table should still be enforced.  For example, if you shorted the DAC output to 10V, you would have exceeded the abs. max voltage and could damage the device.