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ADS8328 High Vref

Adrian Soltero
Intellectual 1135 points

Other Parts Discussed in Thread: ADS8328

Hi,

 

I am working with the ADS8328 and I have a couple questions with having the following settings:

VA = 5 V, VBD = 3.3 V, REF+ = 4.5 V

  1. What is the impact of using a REF+ slightly higher than the rated max of 4.2 V (for VA = 5 V)?  How would this affect the functionality of the chip?
  2. How does the device behave when the analog input exceeds Vref (reaches 5 V)?  Does the conversion indicate the max value or does the output act differently?
  3. Is there any impact on the long term reliability caused by either REF+ > 4.2 V or IN > REF+?

I am most worried about the long term reliability of having these settings.  Can you give me any guidance here? 

 

Thanks,

Adrian

 

  • 0
    TI__Guru**** 182601 points

    Hi Adrian,

    If you review page 3 of the ADS8328 data sheet, that should answer your long term reliability question (#3 above).  For question 1, there would not be any functional difference in the ADS8328 - it would still convert and provide the INT/EOC output, SDO, etc.  You may also start to see some linearity issues on the high side of the analog input range (beyond the specified 4.2V limit that is).  For question 2, input voltages that exceed the Vref input and are still under the AVdd rail would provide the full scale output code as noted in Table 6.