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ADS7254: when DVDD pin is open, what happens?

Hisao Uchikoshi
Genius 13530 points
Part Number: ADS7254

Hi Experts,

Our system is using ADS7254IRTER. Due to some reasons, we noticed there is a chance that DVDD pin is not powered by 3.3V while AVDD is powered by 5V and REFIO is powered by 2.5V. Under this condition, 

1) Is there any chance for ADS7254 to operate and output any?

2) Is there any path to flow a current from AVDD land to DVDD land?

3) When continuing to use ADS7254 under this condition, what kind of event occur do you think? A permanent damage occurs?

Regards,

Uchikoshi

  • 0
    TI__Guru 57336 points

    Hello Uchikoshi-san,

    In the Absolute Maximum Ratings table, I do not see a restriction between AVDD and DVDD. This should mean that it is ok to apply AVDD and not apply DVDD without causing damage to the device. Make sure that the AVDD voltage remains within the specified voltage range and that the difference between REFGND and GND is less than 0.3 V. 

    When DVDD is not present, the digital interface cannot operate and the device should not output anything.

    Best regards,

  • 0 in reply to Ryan Andrews
    TI__Guru 57336 points

    Hello Uchikoshi-san,

    The design team has provided some additional feedback. They do not expect any damage to the device when AVDD is powered without DVDD. The customer may observe marginally higher current from AVDD to GND and the interface will not work without DVDD. Once the DVDD supply is enabled, the device should work normally again.

    Best regards,