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ADS8694: reference dependence on power supply accuracy

Tobias96
Prodigy 70 points
Part Number: ADS8694

Hello, i have a question about the internal reference...

I guess its build from AVDD, which is 5V normally. How is the ref related to the stability of AVDD?

AVDD is generated with a transfomer and i have some noises on 5V supply.

Does it have any affect on the reference?

  • 0
    TI__Mastermind 45515 points

    Hello,

    Thanks for your query on E2E, I will get back to you soon.

    Best regards

    Dale

  • 0 in reply to Dale Li
    TI__Mastermind 45515 points

    Hello Tobias96,

    I missed your query, I apologized for the delay.

    The internal reference (4.096V) on ADS8694 is a band-gap reference which is a very stable voltage reference in regard to both temperature and power supply variations, but the power sources to ADS8694 must be clean and well-bypassed (refer to Layout Guidelines in datasheet), especially for analog power supply AVDD, generally a linear regular (LDO) is recommended for the ADC, otherwise, it will have a significant impact to the performance you measure regarding the noise/ripple on power supply, please refer to below figures for ADS8694's power supply rejection ability:

    Thanks.

    Best regards

    Dale