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ADS131M08: ADS131M08 External Reference Voltage Level

Kaveh Mohammad
Prodigy 110 points
Part Number: ADS131M08

Hi, 

I am using ADS131M08QPBSRQ1 in my design. Its internal reference is only 1.2V which is very low and impose a lot of constraints to my design. I have these questions:  

1- What is the maximum reference voltage that can be applied to REFIN pin of this ADC? Can I supply this pin with a 3.3V reference voltage?

2- What is the recommendation on supplying this chip? Should I connect DVDD digital supply to a typical 3.3V and the analog supply AVDD and REFIN pin should be connected to my high precision 3.3V reference voltage? 

3- If I connect my analog supply AVDD and REFIN pin to a 3.3V reference chip, what is the required current to supply these pins from the reference chip? 

Thanks 

  • +1
    TI__Mastermind 21115 points

    Hello Kaveh,

    thanks a lot for your interest in our ADS131M08-Q1.

    The allowed reference input voltage range is specified in the "Recommended Operating Conditions" table in the datasheet. It is limited to 1.3V (max).

    You don't need to supply AVDD from a high precision reference voltage. The device offers good PSRR.
    Most customers power AVDD and DVDD from the same 3.3V supply. Ideally the 3.3V supply would be generated using a linear regulator, and not a switching regulator.

    If you don't want to use the internal voltage reference, then use a precision external voltage reference connected to the REFIN pin.

    You can find the current draw of the supplies in the "Power Supply" section of the "Electrical Characteristics" table in the datasheet.

    Regards,
    Joachim Wuerker