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Original question:

DAC9881: Glitch Reduction

DAC9881: Glitch Issues in DAC

Martin Stougaard
Prodigy 120 points
Part Number: DAC9881
Other Parts Discussed in Thread: TIPD142, DAC8811

Hi

I am trying to reject glitches from a DAC. We want highest possible resolution (about 18 or 20 bit) in a bipolar output of +-10V.

If we select the DAC9881 some glicht will occur. I have looked at the: http://www.ti.com/tool/TIPD142

This will help according to the note - but still some glitch will occur. 

How can we make this work with +-10V output?

regards

  • 0
    TI__Genius 14220 points
    Hi Martin,

    Thank you for your query. It is true that the code-to-code glitch cannot be made zero. However, it can be made insignificant enough for a given application. This will have tradeoff with other parameters like settling time. Could you please provide more details on your application and how you think the code-to-code glitch is going to impact? That will let us suggest more specific answers.

    Regards,
    Uttam Sahu
    Applications Engineer, Precision DACs
  • 0 in reply to Uttam Sahu
    TI__Genius 14220 points
    Hi Martin,

    Do you have an update on this?

    Regards,
    Uttam
  • 0 in reply to Uttam Sahu
    Prodigy 120 points

    Hi

    Some guidelines for the DAC.

    - We want a bandwidth of at leaset 100kHz (200kS/s).

    - Since we ramp the signal in different ways (exponential, sawtooth etc) we dont want glitches.

    - We want 16 bits or higher

    - We have tried implementing an external s/h filter to reduce glitches at major code changes. This does not seem to help because the analog switch introduces switching noise in the signal chain. Maybe the TIPD142 app-note is a better answer. They use a TS12A4515DBVR.

    regards.

  • 0 in reply to Martin Stougaard
    TI__Genius 14220 points

    Hi Martin,

    Apologies for the delay. If you need 18-bit resolution, we only have DAC9881 in our portfolio. But if you can manage with a 16-bit resolution, we have a family of MDACs that are geared for very low glitch and higher update rate requirements. You can look at DAC8811 to start with.

    let me know if that helps.

    Regards,

    Uttam