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ADS8363 Power sequence

Bogdan Nicola
Prodigy 140 points
Other Parts Discussed in Thread: ADS8363

Hi,

Could you please advise regarding the ADS8363 power sequence?
The ADS8363 will be used in a control system.

According to the datasheet: Supply voltage, DVDD to AVDD = 1.2 × AVDD.

Does this limit also apply during power-up and power-down.
For example if DVDD and AVDD rise simultaneously, the limit DVDD>1.2*AVDD is not fulfilled for low voltages.

If  linear regulators will be used for the supply rails to avoid a more controlled power-sequencing. Is this possible?
What are the power-down limits or recommendation?

Thank you in advance for your support.

Kind regards,

Bogdan

  • 0
    TI__Mastermind 45285 points

    Hi Bogdan,

    The Absolute Maximum Ratings in the data sheet states what maximum voltages, currents, or temperatures can be applied to the pins or case of a device to avoid causing damage to the device.

    For ADS8363, Absolute Maximum Ratings table shows that the difference between DVDD and AVDD should be less than 1.2xAVDD, it shows that there is a restriction between DVDD and AVDD, it states that AVDD must be powered up before or at the same times as DVDD, but DVDD value can be only a maximum of  2.2 times AVDD. The analog and reference inputs have a restriction as well that these inputs can't  exceed AVDD+0.3V or AGND-0.3V, this shows AVDD should be powered up firstly or at the same time but these inputs are limited between +/-0.3V, if the analog or reference inputs is present before AVDD, the analog core powers up in a probable latch-up state, the current through AVDD can be much higher than the specification in the datasheet and cause ADC to be pretty hot. There is a same requirement for the digital inputs and DVDD.

    When powering off, a reverse order is required to meet the specification in the Absolute Maximum Ratings table as well.

    Hopefully this is helpful to you. Thanks.

    Best regards

    Dale Li

  • 0 in reply to Dale Li
    Prodigy 140 points
    Hi Dale,

    Thank you very much for the info.
    Kind regards,
    Bogdan