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ADC32RF45: The settings of emphasis in DATASHEET(Real) and ADC32RF45 AMI Model TX are different.

DONGHO YU
Prodigy 175 points
Part Number: ADC32RF45

Hi,

I use ADC32RF45. I try to simulate with its IBIS AMI Model for JESD.

By the way the settings of emphasis in DATASHEET(Real) and ADC32RF45 AMI Model TX are different.

In TX AMI Model, I can set from 0 to 6 in emphasis. In 7page of ADC32RF45_AMI_users_guide.pdf, there is Description that Higher value has more emphasis.

But in table68(91page) of the datasheet, there are emphasis setting from 0(0dB) to 63(-11.5dB).

How should I match emphasis in AMI Model to real datasheet?

Thank you.

dongho

  • 0
    TI__Mastermind 29220 points

    Hi,

    I have asked the design team about this, and will follow up with what I find out.

    Regards,

    Richard P.

  • 0 in reply to Richard Prentice
    Prodigy 175 points

    Hi,

    I see adc32rf45.pdf SBAS747C-MAY2016-REVISED DECEMBER 2016 for datasheet.

    If I should see the other document for setting JESD TX emphasis, plz let me know the name of the document and the page.

    Thank you.

  • 0 in reply to Richard Prentice
    Prodigy 175 points

    Hi Richard,

    Can I know when I get your reply from design team?

    Or can I get his e-mail address or let him join this conversation?

    Regards,

    Dongho

  • 0 in reply to DONGHO YU
    TI__Mastermind 29220 points

    Hi,

    I have just heard that the design team has started to look into this, and that they expect to get back to me next week by Tuesday.

    Regards,

    Richard P.

  • 0 in reply to Richard Prentice
    TI__Mastermind 29220 points

    Hi,

    From the design team:

    Here is the mapping:

    De-emphasis setting in model = Register bit SEL EMP LANE x <5:0>

    0=000 000

    1=000 001

    2=000 011

    3=000 111

    4=001 111

    5=011 111

    6=111 111

     

    The datasheet has a 6-bit register field for de-emphasis settings, with 7 amounts of de-emphasis listed and the value to write into the register field for each.

    From the datasheet, and changing the decimal to binary:

    These bits select the amount of de-emphasis for the JESD output transmitter. The de-emphasis value in dB is measured as the ratio between the peak value after the signal transition to the settled value of the voltage in one bit period.

    000000 = 0 dB

    000001 = –1 dB

    000011 = –2 dB

    000111 = –4.1 dB

    001111 = –6.2 dB

    011111 = –8.2 dB

    111111 = –11.5 dB

    So the mapping from these 7 settings to the value in the model is:

    0=000 000

    1=000 001

    2=000 011

    3=000 111

    4=001 111

    5=011 111

    6=111 111

    Regards,

    Richard P.

     

  • 0 in reply to Richard Prentice
    Prodigy 175 points

    Hi,

    I understand that In Table68 of adc32rf45 datasheet, 0/1/3/7/15/31/63 values are for register setting and 0/-1/-2/4.1/-6.2/-8.2/-11.5dB are matched to 0~6 AMI setting value in order.

    Thank you so much.

    Regards,

    Dongho.