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ADS7865: Power-up sequnce/down sequence

Oba
Genius 16775 points
Part Number: ADS7865

Tool/software:

Hello,

ADS7865 has 2 power supplies. Does it require any specific power-up/down sequnce for these supplies?

Regards,
Oba

  • 0
    TI__Intellectual 2160 points

    Hello Oba, 

    This device does not specify power on/off sequencing, but if some sequencing is necessary/possible, we recommend following:

    1) Power AVdd on before BVdd (or bring both up together)
    2) Power down BVdd before AVdd (or bring them down together)

    Best regards, 

    Yolanda

  • 0 in reply to Yolanda Gonzalez
    TI__Genius 16775 points

    Hello Yolanda,

    Thanks for your reply.
    What is the reason for your recommendation?
    What could happen if BVdd is powered up before/powered down after AVdd?

    Regards,
    Satoshi Obata

  • 0 in reply to Oba
    TI__Intellectual 2160 points

    Hello Satoshi Obata, 

    When regarding the absolute maximum values, BVDD is set as function of AVDD ( max BVDD =  1.5xAVDD) . So it is only a precaution, in case there is any control, but the device should be functional regardless of the power sequencing as long as both supplies are in their recommended range when using the device. 

    Does your system have a possibility of a vast difference in ramp up times and speeds? If so, could you share the expected rates? I can look closer into those scenarios if it would help.

    Best regards, 

    Yolanda

  • 0 in reply to Yolanda Gonzalez
    TI__Genius 16775 points

    Hello Yolanda,

    Thanks. I didin't notice that BVdd is specified as <1.5 x AVDD in abs max.

    Regards,
    Satoshi Obata