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ADS61B49: AVCC/AGND and DRVDD/DRGND

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Replies: 8

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Part Number: ADS61B49

Dear Technical Support Team,

 I have three questions about ADS61B49. See attached file.

8132.ADS61B49_AVDD_DRVDD.pptx

 Q1)

Could you show the region of AVDD/AGND and DRVDD/DGND for each pins?

If I have missunderstanding, could you fix it correct?

 

I refer to the PCB and schematic of ADS6125EVM below.

www.ti.com/.../ads6125evm

www.ti.com/.../slar115

 

Q2)

Should SEN pin of ADS61B49 connect AGND(Analog Ground)?

I found slightly difference of ground between ADS61B49 and ADS6125.

SEN pin of ADS61B49 is used with AVDD(Analog Power)

The one of ADS6125EVM is used with DRVDD(Digital Power)

 

Q3)

ADS61xxEVM have single point earth between AGND and DRGND.

Should ADS61B49 set single point earth between AGND and DRGND?

 

Best Regards,

ttd

  • Hi ttd,

    We are looking into this.

    Thanks,
    Eben.
  • In reply to Ebenezer Dwobeng:

    Hi Eben,

    Thank you for your reply.

    I'm looking forward to your answer.

    Best Regards,

    ttd

  • In reply to ttd:

    Hi Eben,

    Do you have any update so far?
    Thank you for your cooperation.

    Best Regards,

    ttd
  • In reply to ttd:

    Hi ttd,

    Q2) Connect SEN to digital ground. This is enable for the SPI interface
    Q3) Yes, use the same single point earth connection on the ADS61xx EVM also on the ADS61B49EVM

    Thanks,
    Eben.
  • In reply to Ebenezer Dwobeng:

    Q1) I'm looking forward your  reply.

    >Q2) Connect SEN to digital ground. This is enable for the SPI interface

    ⇒ The datasheet of ADS61B49 said that SEN has internal pullup to AVDD(analog power).

        Is it ok to connect pullup(AVDD) to DRGND(digital ground)

    >Q3) Yes, use the same single point earth connection on the ADS61xx EVM also on the ADS61B49EVM

    ⇒I understand.

    Best Regards,

    ttd

  • In reply to ttd:

    Hi ttd,

    Q1) Can you elaborate more on this because I am not sure what is needed here. I believe the PCB layout file should have all that you need.
    Q2) Connect AVDD to AGND not DGND. The pullup on SEN is weak so it will not affect the AGND

    Thanks,
    Eben.
  • In reply to Ebenezer Dwobeng:

    Hi Eben,

    Q1)

    OK, just simple question, I'd like to know that pins should be connected which region  AGND or DRGND.

    I attached my understanding from your answer of Q2 and PCB of EVM. so I think that it is correct, right?

    Q1_ADS61B49_AVDD_DRVDD.pptx

    Best Regards,

    ttd

  • In reply to ttd:

    Hi ttd,

    This should work. You are right that SEN should be treated as part of AGND domain since it is internally connected to AVDD

    Thanks,
    Eben.

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