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ADS1278: Power sequence issue

Randy Wang
Intellectual 1705 points
Part Number: ADS1278


Hi Team,

  My customer is using ADS1278 for metering application, they're powering device by 3.3V IO, 1.8V DVDD, 5V AVDD sequence (datasheet suggest DVDD, IO, AVDD), 3.3V also power DSP which controls 1.8V.

  The problem is when 3.3V powered up, it seems ADS1278 draws a lot of current (about 400mA) and AC-DC power supply failed, so the system can not work properly, so I'm wondering if you can comments why ADS1278 draws more current when 3.3V IO first power up. thanks. 

Best Regards,

Randy Wang

  • 0
    TI__Guru 67206 points
    Hello Randy,

    Thank you for your post.

    The reason behind the suggested power-up sequencing is to ensure proper initialization. This should not cause any damage to the device or draw unexpected amounts of current from the supply source.

    Where exactly does the customer measure 400 mA? Can you verify how much current each ADS1278 supply is drawing?

    Regards,
  • 0 in reply to Ryan Andrews
    TI__Intellectual 1705 points

    Hi Andrew,

      Thanks for your comments. It's hard to measure all 3 power rail supply current, in this case 1.8V is not powered up so it's definitely 0. so I think 3.3V draws the most current. 

    Best Regards,

    Randy Wang