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ADS7953: Output when 2xVREF > +VA

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Part Number: ADS7953

Hi Team,

ADS7953 datasheet tells that if full-scale input span is set to Range 2, 2xVref should be no higher than +VA, may I know what will be the output if 2xVREF > +VA?

For example, Vref is 2.5V, +VA is 5V provided by the LDO, the LDO output cannot be always be 5V due to the accuracy error, what will it be if the LDO output changes to 4.95V?

Thanks and Best Regards!

Hao

  • Hello,

    This restriction is due to the ESD protection. There is internal diodes for protection.

    We recommend that VA is always higher or equal to Vin as the internal diodes are connected between the analog input and VA.

    If Vin is higher, then the diode will turn on. This is not desired during normal operations

    But, as long as the Vin is not 300mV greater than VA, then this should not be an issue

    The LDO output will likely not have a swing that large, thus you should be fine

    Regards

    Cynthia

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