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DAC34SH84EVM: Problem of schematic of DAC34SH84 and FMC-DAC adapter

Long Hoang44
Intellectual 400 points
Part Number: DAC34SH84EVM
Other Parts Discussed in Thread: DAC34SH84, FMC-DAC-ADAPTER

Hej all,

I am using DAC34SH84EVM rev D (which I guess it is reference D) and FMC-DAC adapter rev D. I did cut off the tab to make them being able to connect.

Now I have another issue that make me confused 

1. At DAC34H8x EVM Interface (rev D) pins at 180-pin connector are different with the pins at FMC-DAC adapter rev D, while at DAC34H8xEVM rev C  the pins at ASP-122952-01 are compatible with FMC-DAC adater rev D. It means that I have to change the board to rev C, doesn't it?

2. In the FMC-DAC adapter, there are 4 pins (they are IO-DB1P-N, IO-DB0P-N) not being available on the FMC connector. They are available on the connector ASP-122952-01. Is this a bug?

Thank you for your help.

Long 

  • 0
    TI__Genius 12780 points
    Hi Long,

    I am taking a look at the schematics, and will get back with you soon.

    Regards,

    Dan
  • 0
    TI__Genius 12780 points

    Hi Long,

    The FMC_DAC_Adapter Rev D will map correctly to the DAC34SH84 EVM Rev D. Looking at ASP-122953-01 on the FMC_DAC_Adapter Rev D schematic (included in the attached word document), you will notice that the reason this connector is 160 pins, instead of 180, is that one pin was removed for every two pins on J2A. In practice, this has no effect on where the active pins are located, and provides more isolation for the pins on this connector. If you count out the pins on J2A FMC-DAC-Adapter REV D and compare with J13B of DAC34SH84 REV D, you should see what I am describing.

    You are correct about DB0 and DB1 not being on the FMC connector. We are in the process of getting this corrected. Since these two bits are LSBs, there should be little effect on your output. I think you may see one dB of degradation in performance overall, but should still be sufficient for testing purposes.

    Regards,

    Dan

    DAC34SH84_Connectors.docx

  • 0 in reply to dBrock
    Intellectual 400 points

    Hej,

    OK now I get your point of design. I will let you know if the DB0 and DB1 do have an effect or not as I do the test.

    Anyway, thank you for  your help. You should explain somewhere in the document, Otherwise, it will confuse customers.

    Long

    Daniel Brock36 said:

    Hi Long,

    The FMC_DAC_Adapter Rev D will map correctly to the DAC34SH84 EVM Rev D. Looking at ASP-122953-01 on the FMC_DAC_Adapter Rev D schematic (included in the attached word document), you will notice that the reason this connector is 160 pins, instead of 180, is that one pin was removed for every two pins on J2A. In practice, this has no effect on where the active pins are located, and provides more isolation for the pins on this connector. If you count out the pins on J2A FMC-DAC-Adapter REV D and compare with J13B of DAC34SH84 REV D, you should see what I am describing.

    You are correct about DB0 and DB1 not being on the FMC connector. We are in the process of getting this corrected. Since these two bits are LSBs, there should be little effect on your output. I think you may see one dB of degradation in performance overall, but should still be sufficient for testing purposes.

    Regards,

    Dan

    (Please visit the site to view this file)