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DAC80508: About powerup sequence of External reference input

Guru 21045 points
Part Number: DAC80508

Hi Team,

 

I set “CONFIG register bit8(REF-PWDWN)=1” to use External reference input.

Then, I would like to apply External reference voltage before than set “CONFIG register bit8(REF-PWDWN)=1”.

 

[Sequence]

1.Apply to External reference voltage

2.Set “CONFIG register bit8(REF-PWDWN)=1”

 

Could you please let us know if you have any concern and suitable sequence?

 

Regards,

Hide

  • Hi Hide,

    in DAC80508, by default internal reference is enabled which means if you apply external reference input on power up, there can be sourcing or sinking current from external to internal or vice versa depends on the voltage.

    May I know what is the external reference voltage you are applying? If its 2.5V, I don't see much of an issue with your sequence as internal reference is also at 2.5V. But if you plan to use more than 2.5V, momentarily there can be current flowing from external reference to internal reference circuit internal to device.

    You can proceed with this sequence as soon as you power up the device. We dont recommend connecting external reference to REFIO and not configure the register for long time.

    Regards,

    AK

  • Hi AK-san,

    Thank you for your prompt reply and information.

    Regareds,

    Hide