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ADS8912B: Power On Reset

Taketo Sato
Genius 9475 points
Part Number: ADS8912B

Hello team,

I have a question about power-on-reset requirement of ADS8912B.

I think ADS8912B has power on reset feature and RVDD is important for the feature when power up.

Could you let me know if there is any requirement on RVDD ramp so that ADS8912B can properly do power on reset?

Best regards,

  • 0
    TI__Mastermind 36240 points

    Hello Sato-san,

    Yes, the ADS8912B has an internal power-on reset circuit, and it is powered from the RVDD supply voltage.  

    Section 9 of the datasheet provides the requirements for a proper power-on reset.  Once RVDD exceeds 0.7V, it needs to rise monotonically to the minimum operating voltage of 3V.

    Regards,
    Keith Nicholas
    Precision ADC Applications

  • 0 in reply to Keith Nicholas
    TI__Genius 9475 points

    Hello Keith-san,

    Thank you for your comment.

    Keith Nicholas said:
    Once RVDD exceeds 0.7V, it needs to rise monotonically to the minimum operating voltage of 3V.

    So if slew rate or slope of RVDD waveform is always positive between 0.7V and 3V like below image, it should be ok, correct?

    Then, do we have slew rate or time requirement(min/max) on RVDD between 0.7V and 3V?

    Best regards,

  • +1 in reply to Taketo Sato
    TI__Mastermind 36240 points

    Hello Sato-san,

    Yes, your understanding is correct.  The above waveform will meet the power-up requirements.

    We do not have any timing requirements or recommendations for the slew rate.  The devices are typically tested with ramp times in the range of 0.1V/ms to 10V/ms.

    Regards,
    Keith