• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 46 subscribers
  • Views 256 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DAC121S101QML-SP: Noise Data

Mitchell
Expert 4915 points
Part Number: DAC121S101QML-SP
Other Parts Discussed in Thread: LM4050QML-SP

Hi Team,

My customer is looking at using the DAC121S101QML-SP for an application that requires low 1/f noise, in the 0.1 - 10Hz range. This part would likely be fed by a LM4050QML-SP reference. 

Do we have any data available that proves this part would be a good fit?

Thanks,
Mitchell 

  • 0
    TI__Mastermind 18546 points

    Hi Mitchell,

    I will try to get this info from my team, Please allow a day or so

    Regards,

    AK

  • 0 in reply to Akhilesh K
    TI__Mastermind 18546 points

    Hi Mitchell,

    Please find the info below. I dont know whats your target 1/F noise should be

    The LM4050 noise can be mitigated with an output cap. You should use cap on LM4050 to mitigate SETs (see rad report in the product folder under Technical documents), and this should be good part to go with DAC121S101QML-SP.

    Also please find info of 1/F noise for DAC.

    Spot Noise (output, volts squared)

    1 Hz       1.87 e-12

    10 Hz     2.88 e-13

    100 Hz   4.5 e-14

    1kHz      7.3 e-15

    Integrated noise (output, volts squared)

    1Hz-100 MHz        1.47e-8

    We didn't really measured noise down to 0.1Hz due to set up constraints. Also you can extrapolate this data to get noise at 0.1Hz, since these follows an inverse decade relationship with frequency (may not be accurate though).

    Regards,

    AK

  • 0 in reply to Akhilesh K
    TI__Expert 4915 points

    Hi AK,

    Thanks for the info!

    They plan a 3 pole ~50Hz low pass passive output filter after the DAC / current source driver.

    They have a requirement for somewhere in the range of 1uV to 3uV integrated noise below 10Hz (whether the low frequency cutoff is 0.1Hz or 0.01Hz is under discussion. That is relative to a 3V output. Specs are not solid yet because a variety of parameters for the project are still being optimized.

    There is an additional temperature coefficient requirement on the order of 20ppm/C.   (that is still uncertain because we don’t know the temperature stability spec of the electronics platform in operation, and we may drive that spec).

    Are your spot noise measurements in a 1Hz bandwidth?  (for 1Hz, did you scale from a narrow band measurement?)

    Based on your spot noise you have what looks like around a 1KHz 1/f corner.  As  a rough guess, that  would put the integral around 5uV down to 0.1 Hz.That is in the right range for what we are looking for.

    If you had  0.1Hz data that would help but we can estimate from what you have.

    Thanks,
    Mitchell

  • 0 in reply to Mitchell
    TI__Mastermind 18546 points

    Hi Mitchell,

    This is the data we have as of now. I can definitely test it out after this COVID 19 situation get over.

    Yes, the bandwidth of measurements for spot noise is 1Hz, by looking at the data I received.

    Down to 0.1Hz measurements is little bit tricky though. What kind of applications is this? If you are not feeling to discuss this in e2e, we can always take this conversation to emails.

    Let me know if you need more help regarding the same.

    Regards,

    AK