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Original question:

[FAQ] ADS1278-SP: Power on / off (up / down) sequencing requirements

ADS1278-SP: power-up sequence

Noriyuki Takahashi
Genius 9780 points
Part Number: ADS1278-SP
Other Parts Discussed in Thread: ADS1278

Tool/software:

Hi team,

Please let me confirm below just in case.

Could you tell whether there are any time restrictions that they need to follow for the power sequence?
There are no descpritions about the time restriction in 10 Power Supply Recommendations in the datasheet.

Regards,

Noriyuki Takahashi

  • 0
    TI__Mastermind 38191 points

    Hi Noriyuki Takahashi

    Can you help us track this opportunity by posting the customer name in the Notes section of the Thread Tracking Toolkit?

    -Bryan

  • 0 in reply to Bryan Lizon86
    TI__Genius 9780 points

    Bryan,

    I posted.

    Regards,

    Noriyuki Takahashi

  • +1 in reply to Noriyuki Takahashi
    TI__Mastermind 38191 points

    Hi Noriyuki Takahashi

    Thanks for providing the requested info

    The power-up sequence for ADS1278 is only required for proper operation of the internal power-up reset circuit.  As long as DVDD reaches 1V or greater before IOVDD starts to ramp, and IOVDD reaches 1V or greater before AVDD starts to ramp, then the internal power-up circuit will operate properly. The time between each power rail then depends on the ramp rate.  If it is 1V/500uS, then you would need to wait 500uS, but if it is much quicker, such as 1V/100uS, then you would only need 100uS between each power rail.

    Please note that even if you meet all power-up requirements, we still recommend asserting the /SYNC pin after all power supplies have reached the nominal levels and data first appears.  This ensures proper operation in cases where the supplies are shut-down and the bypass capacitors are not allowed enough time to fully discharge before power is reapplied.

    -Bryan