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ADS7953: analog input

Danilo A.
Mastermind 33505 points

Part Number: ADS7953

Hi Team,

Posting on behalf of our customer.

In our design, we are using the ADS7953SBRHBR ADC with a reference voltage of 2.5 V. The analog input is 3.3 V, and the digital input is 2.5 V. Both the 3.3 V and 2.5 V rails are expected to come up at approximately the same time during power-up.

However, one of the analog inputs is derived from a 24 V source, which we scale down by a factor of 1/13 using a 120 kΩ and 10 kΩ resistor divider. This means that the scaled voltage will be present on the ADC input significantly earlier than the 2.5 V and 3.3 V supplies.

Our concern is whether this condition could cause the ADC to latch up or experience any reliability issues. Could you please share your insights or recommendations on this scenario? 

Regards,

Danilo

  • 0
    TI__Mastermind 20470 points

    Hi Danilo,

    Sorry for the late reply on this. 

    So long as the input current is limited to below 1mA, this should not be a concern. In this case, it is about 200uA, so there is no concern in damaging the inputs or long-term reliability.

    Regards,
    Joel