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ADS1232: switch on/off AVDD supply

JUNG MOON HWANG
Prodigy 20 points
Part Number: ADS1232

We use half bridge sensor and sample every 10minutes.

The half bridge swing from 0 to Vcc just like a potentiometer(5k).

Q1> Is it ok if we switch on/off the AVDD to save power after PWDN low?

Q2> We put voltage divider for AIN-N since our sensor is half bridge. do you have any other suggest?

Thanks.

  • 0
    TI__Mastermind 41200 points

    Hello Jung,

    Welcome to the TI E2E community.

    You can switch AVDD on/off, but you will need to do a full reset after each power cycle of AVDD, per Figure 8-15 in the datasheet.  Also, if you are using the offset calibration function, you will also need to this after each power cycle as well.

    I think a voltage divider should work.  I suggest using the same resistor values as the typical values in the half bridge.

    The primary support engineer for this part is on vacation and may have some additional suggestions when he returns.

    Regards,
    Keith Nicholas
    Precision ADC Applications

  • 0 in reply to Keith Nicholas
    TI__Guru** 113765 points

    Hello Jung,

    I don't have much to add to what Keith has already stated. When switching off AVDD, you should first set the PDWN pin low.  When AVDD is reapplied, the PDWN pin should stay low until the supply has become stable following Figure 8-15 as Keith has mentioned.  The required timing is given in Table 8-13.

    The voltage divider allows the measurement to be made in a pseudo-differential way increasing the overall dynamic range.  The only potential issue using this method is with any drift of the resistor values over temperature.

    Best regards,

    Bob B