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DAC8760EMC-EVM: Question about noise

ttd
Mastermind 8760 points
Part Number: DAC8760EMC-EVM
Other Parts Discussed in Thread: DAC8760, DAC7750, TIPD153, TIDA-00170, DAC8750

Tool/software:

Dear Technical Support Team,

I have a question about “DAC8760EMC-EVM”.
I have a concern about the noise immunity of DAC8760 and would like to measure the noise immunity with an evaluation board.

(1) I am planning to purchase “DAC8760EMC-EVM”.
　　　The package is VQFN. Is there any difference in noise immunity between VQFN and HTSSOP?
　　　Is the noise immunity of 16bit HTSSOP ≥ 12bit VQFN?

(2) This evaluation board is listed as compatible with windowsXP or windows7, but can it be operated with
win10 or win11?

(3) This evaluation board is described as having a protection circuit compliant with “IEC61000-4”.
Which noise level does it correspond to for each test?

(4) The data sheets of “DAC8760” and “DAC7750” are different in terms of ESD immunity.
Is the overall noise immunity DAC7750 > DAC8760?
　　　Because DAC7750 has a proven track record of adoption and has some noise countermeasures
DAC8760 will be because we feel the risk is higher if there is further concern.

Best Regards,.

  • 0
    TI__Guru* 98515 points

    TTD,


    First, I think this EVM is based on one of the TI designs that we did for the DAC8760. This design passed a set of IEC61000-4-2/3/4/6 tests. The design is written up as TIPD153, but there's no writeup in this folder which can be found below.

    https://www.ti.com/tool/TIPD153

    However, I was able to find another design that did use the DAC8760 and passed a set of IEC61000-4 tests. This design did have more about the tests that passed and some more documentation:

    https://www.ti.com/tool/TIDA-00170
    https://www.ti.com/lit/pdf/TIDU392

    Here are some answers to your questions:

    1. I'm not aware of any difference in noise immunity between the two different packages of the DAC8760. I would guess that both are the same for this characteristic.

    2. The EVM board was designed and built when Windows 7 was the standard operating system at the time and we probably made sure that it operated for Windows XP as well. However, I do use this EVM regularly, and I'm currently running Windows 11. I've also run this EVM with Windows 10 without problems.

    3. According the TIPD153 folder, the board passed IEC61000-4-2/3/4/6 tests. Unfortunately, this folder doesn't have a write up to show the tests. Again the DAC8760EMC-EVM is based on the TIPD153 design and you can compare the schematics of both. Again, the TIDA-00170 writeup does have more description about the IEC61000-4-x tests, but it only describes the IEC61000-4-2/3/5 tests.

    4. The two devices are different in terms of ESD ratings. The DAC8760 has a voltage output added to all of the other features that the DAC8750 has. I think this makes the DAC8760 more susceptible to ESD with more connections to the device. However, I don't think ESD rating and noise immunity are very related. ESD is specifically a device level test, while these IEC61000-4-x tests are board level tests.


    Joseph Wu

  • 0 in reply to Joseph Wu
    Mastermind 8760 points

    Hi Joseph,

    Thank you for your reply.

    TI Designs(TIPD153 and TIDA-00170) are helpful information for me to undestnad IEC61000-4-x tests  for DAC8760.

    I will check these documents.

    I'd like to confirm your answer. 

    Joseph said:

    3. According the TIPD153 folder, the board passed IEC61000-4-2/3/4/6 tests. Unfortunately, this folder doesn't have a write up to show the tests. Again the DAC8760EMC-EVM is based on the TIPD153 design and you can compare the schematics of both. Again, the TIDA-00170 writeup does have more description about the IEC61000-4-x tests, but it only describes the IEC61000-4-2/3/5 tests.

    →DAC8760EMC-EVM product page seems not to provide shcematic. User guide said see TIDP153 for circuit and layout.

       So I think DAC8760EMC-EVM and TIDP153 are same schematic.

    　DAC8760EMC-EVM Evaluation board | TI.com

       Also,  TIDA-00170 shows the test result for IEC61000-4-2/4/5.  Just in case, is IEC61000-4-2/3/5 typo?

    4. The two devices are different in terms of ESD ratings. The DAC8760 has a voltage output added to all of the other features that the DAC8750 has. I think this makes the DAC8760 more susceptible to ESD with more connections to the device. However, I don't think ESD rating and noise immunity are very related. ESD is specifically a device level test, while these IEC61000-4-x tests are board level tests

    →My original question is that  “DAC8760” and “DAC7750” are different in terms of ESD immunity. could you check it again for “DAC7750”.

    Thank you for your cooperation.

    Best Regards,

    ttd

  • 0 in reply to ttd
    TI__Guru* 98515 points

    TTD,


    The schematic for the DAC8760EMC-EVM is in the User's Guide near the end of the document. You can find the document here:

    https://www.ti.com/lit/pdf/SBAU229

    Yes, TIDA-00170 shows test results for IEC61000-4-2/4/5, I had made a mistake on the last post. There is another document describing these specific tests here:

    https://www.ti.com/lit/pdf/SLVA711

    The DAC8750 is the 16-bit version of the DAC7750 which is 14-bit. For ESD, these two are basically identical devices and would perform the same. Again, I think that the DAC8760 is more susceptible to ESD because of the addition of the VOUT DAC and more connections to the device.


    Joseph Wu

  • 0 in reply to Joseph Wu
    Mastermind 8760 points

    Hi Joseph ,

    Thank you for your answer.

    I would like to know the test levels for each test. 
    The materials indicate that IEC 61000-4-2 is conducted at level 4, but is my understanding correct?
    I am unsure of the levels for the other tests as well. 
    What are the levels for IEC 61000-4-4 and IEC 61000-4-5?

     

    I'm concerned that when the noise countermeasures for the DAC7750 are applied to the DAC8760, the addition of Vout to the device may cause changes in the internal structure that could result in failure. We would like to know if there are any differences in the device's tolerance, based on our predictions. Is it simply a matter of adding Vout to the DAC7750?

    Best Regards,

    ttd

  • 0 in reply to ttd
    TI__Guru* 98515 points

    TTD,


    I'm not sure what levels the DAC8760EMC-EVM passed for the IEC61000-4-x tests. However, for the TI Design that I mentioned several posts back describe the tests they conducted and what tests passed. For reference, here are the folder and the write up again:

    https://www.ti.com/tool/TIDA-00170
    https://www.ti.com/lit/pdf/TIDU392

    You can compare these tests to the levels in the document describing the IEC61000-4-x tests here:

    https://www.ti.com/lit/pdf/SLVA711

    The TIDU392 document does describe the tests in detail in the different sections describing each test. However the results, described as specifications, are put into a table (page 3):

    For these results:

    IEC61000-4-2
      4-kV contact discharges is Level 2
      8-kV air discharges is Level 3
    IEC 61000-4-4
      ±2 kV at 5 kHz on signal ports is Level 4
    IEC 61000-4-5
      ±1 kV line-earth (CM) on signal ports is Level 2

    I'm not sure what your second question is asking. The DAC8760 adds a 16-bit voltage DAC to the DAC8750, so the addition of the DAC may require some extra protection other than what is needed with just a current output DAC. In the design, we've added some diodes to shunt any surge current, series ferrite beads, capacitance to shunt high frequencies, and a TVS also for surge. The sense feedback can also be further isolated with an op amp set up as a unity gain buffer. We also give other guidance in the data sheet, but the combination of these protections seem to help with these IEC61000-4-x tests.

    Joseph Wu