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DAC7311: digital input level over the range

Akihisa Tamazaki
Genius 11575 points
Part Number: DAC7311

Hello team,

The customer has one PCB designed from years ago which has the DAC7311 digital input signal at 3.3V while the AVDD is 2.5V.
This is violating the absolute the maximum ratings listed in the datasheet; however the PCB has been working fine over the years.


In this situation, the customer has the following question.
Could you help advise the relative risk of this over-limit hazard? And if TI has any risk/margin analysis or test data similar to this condition?


Basically, I understand that TI cannot guarantee this situation, but customer wants some comments from BU, so please advise me what I should comment to the customer.

Best Regards,
Akihisa Tamazaki



  • 0
    TI__Mastermind 18946 points

    Hi,

    All the digital inputs may have ESD protection diodes connected to AVDD supply. Since you are operating AVDD at 2.5V and IO voltage at 3.3V levels, there is possibility that if  AVDD becomes 2.4V, these diodes can turn on and cause the device not responds to SPI commands.

    (You can infer that there is a protection diode by reviewing the absolute maximum ratings table on page 2 of the datasheet. The potential on any digital input referred to the part's ground is from -0.3V to AVDD + 0.3V.)

    Its just that in customer design, they are just bordering around the conditions of forward bias of these diodes.

    As such we don't recommend these conditions and we don't have any test data to validate customer conditions. Parametric degradation, loss of functionality, or permanent damage could occur.

    Regards,

    AK