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ADS8910B: Power Sequence

Part Number: ADS8910B

Hello,

I would like you to confirm power sequence(both power up and down) requirement for this device.

According to datasheet, I understood REFIN should be ramped up after AVDD reach expected voltage.

However, I'm not sure relationship between AVDD and DVDD.

If you have any requirement for power sequence except above, could you please let me know ?

Especially, I would like you to confirm about below.

* Sequence :

(I'm concerned about  which voltage is related to POR)

* Ramp up/down time for each voltage :

Best Regards,

  • Hello Ryuuichi-san,

    There are no special power supply sequencing requirements between RVDD(AVDD) and DVDD, either during power up or power down.  The internal power-on reset circuit is in the RVDD domain, and does require the following to be observed for proper reset of the device.

    During normal operation, if RVDD supply drops below the RVDD minimum specification (3V), ramp the RVDD supply down to ≤ 0.7 V before power-up. During power-up, RVDD must rise monotonically to the recommended minimum operating voltage.


    Other than the above requirement, as long as the ABS Max specifications are met, there are no other power up/down requirements.  However, if there is a concern about proper reset of the device, then issue a reset pulse on the /RST pin after the supplies are powered and stable.

    Regards,
    Keith Nicholas
    Precision ADC Applications

  • Hello Nicholas-san,

    Thank you for your reply.

    Let me confirm about below.

    During normal operation, if RVDD supply drops below the RVDD minimum specification (3V), ramp the RVDD supply down to ≤ 0.7 V before power-up. During power-up, RVDD must rise monotonically to the recommended minimum operating voltage.

    I understood as shown below.

    If my understanding is correct, I have following question.

    * How much time should user wait condition of ”≦0.7V” ?

    Best Regards,

  • Hello Ryuuichi-san,

    I will need to do some research to see if we have any additional data.  Please give me a few days.

    Thank you,

    Keith

  • Hello Ryuuichi-san,

    We found some additional data.  We recommend holding RVDD≤0.7V for at least 200mS (0.2 Seconds) before ramping the voltage back up.

    Thank you,

    Keith

  • Hello Nicholas-san,

    Thank you for your reply.

    Understood.

    BR,