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ADS7951: VDDIO discussion

Lin_Charles
Expert 4260 points
Part Number: ADS7951

Hi team,

It is nice to know you here. My customer wants to know two questions about the VDDIO,

1. What is the risk if VDDIO is larger than AVDD? Such AVDD=5V, VDDIO=5.3V?

2. As our recommend max value for the AVDD is 5.25V, which means max value for VDDIO is 5.25V. What will happen if VDDIO larger than 5.25V?

  • 0
    TI__Mastermind 24940 points

    Hello, 

    1. the device has an internal ESD structure. when VBD is greater than VA, these diodes will begin to conduct, increasing current consumption and potentially deteriorating performance. also this is outside the specs of the datasheet, at that point there is no say as to how the device will response. This can also result in permanent damage to the device, in particular for extended periods of time 

    2. This can result in permanent damage to the device

    If the customer is concerned with possible exposure to over voltage, there is a series of video as part of TI Precision Labs that covers EOS and ESD for ADCs, that I suggest the customer take a look at. these videos explain how the internal structure works, and methods to help protect the ADC

    Regards

    Cynthia

  • 0 in reply to Cynthia
    TI__Expert 4260 points

    Hi Cynthia,

    Thank you for your response here. For questions two, 5.25V does not violate the max value 7V, do you think this will also result in permanent damage to the device?

    BR,

    CL

  • 0 in reply to Lin_Charles
    TI__Mastermind 24940 points

    CL,

    The device can withstand voltages up to the absolute max. Performance though is only tested under the recommended specifications.

    If VBD is greater than VA, but below the Abs max, the device will likely not be damaged, but will affect current consumption and performance. This is acceptable if transients within this range are expected. But this is not good for normal operation. Having VBD higher than VA but within abs max will have the ESD structures continually conducting and this can shorted the life cycle of the device.

    Regards

    Cynthia