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ADS1220 - power voltage limits

FabulousRP
Prodigy 190 points
Other Parts Discussed in Thread: ADS1220

Hi,

we are using ADS1220 in a very low-power End-application.

Before to go in stand-by state we send a POWERDOWN command to ADS1220. When returning to the normal operating state (AVDD = DVDD = 2.3V) we send a RESET command and a complete configuration to ADS1220, before starting any conversion. In the stand-by state, is it possible to have the following power supplies for the ADS1220?

1. Analog Power Supply AVDD = 0V (shut-off),

2. Digital Power Supply DVDSS = 1.8V (the recommended values are 2.3 ~ 5.5V).

Thanks for any help.

Renzo

  • 0
    TI__Guru* 92715 points
    Renzo,


    I would avoid that state. While I don't have any knowledge of anything bad happening with such a condition, I don't know if anyone has fully characterized what happens when it is set there for an extended period.

    With the digital supply at 1.8V, it would be case of brownout voltage as when there is a momentary loss in power. At this voltage, it's possible that the digital circuits could change register values or get lost in the SPI state. Also, I'm not sure if there are any other unusual effects, such as extra supply current.

    The ADS1220 does have a good internal power-on reset and the device can be powered up with either the analog or digital supplies first. However, I still like to have the power come up to a known usable state, instead of having it hang out at a level which things are not settled.

    I'll ask the development team if there was any characterization done with this type of condition and I'll report back if there is any data.


    Joseph Wu
  • 0 in reply to Joseph Wu
    Prodigy 190 points

    Thank you, Joseph, have you news about " I'll ask the development team if there was any characterization done with this type of condition and I'll report back if there is any data. "?

    Bye.

    Renzo

  • 0 in reply to FabulousRP
    TI__Guru** 112935 points

    Hi Renzo,

    We do not have any further information to share.  1.8V is outside of the normal operating parameters for this device and the operation is unpredictable and may change from part to part.  It is not recommended to operate the ADS1220 in this way.

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Prodigy 190 points

    Thank you, Bob.

    Best Regards.

    Renzo P.