• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 45 subscribers
  • Views 325 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

DAC82002: Spec sheet clarification

Lorinc Sárkány
Prodigy 10 points

Part Number: DAC82002
Other Parts Discussed in Thread: DAC8830, DAC81001

Tool/software:

Hi,

I'm in the process for selecting a proper DAC for our application. I'd like to optimize for lowest possible noise between 0.1 -- 150 Hz. DAC82002 is one candidate, however, I'd have some questions regarding its spec sheet. Could you please help clarifying these issues?

  1. Noise density: Sec. 6.5 table vs. Fig 6-21. According to the former, noise density is 10 nV/sqrt Hz at midcode, but the figure shows around 30 nV/sqrt Hz, at an unspecified code. Where is this discrepancy coming from? Does the noise depend this heavily on the code or is it an error in the spec sheet? Could you offer a graph about the code-dependence of the noise?
  2. I'm trying to compare this DAC's performance with DAC8830 (which is what we are using currently in our product), however, the DAC8830's spec sheet offers very little detail. Neither the full noise density spectrum, nor the integrated total low-frequency noise is specified. Could you please provide these information too, so I can compare the two products directly?
  3. Compared to DAC82002, DAC81001 offers lower noise density at 1 kHz, yet the total integrated noise on 0.1 Hz -- 10 Hz seems to be a factor 4 lower for DAC82002. Could you please confirm this? Unfortunately, the noise spectrum graph for DAC81001 is incomplete, it's only shown for f > 500 Hz. Do you have a graph for lower frequencies too? It would be critical for us to know.

Thank you for your help!

Best regards,

Istvan

  • 0
    TI__Expert 5030 points

    Hi Istvan,

    I am reviewing this and will get back to you shortly.

    Thanks,
    Lucas

  • 0 in reply to Lucas Burnette
    TI__Expert 5030 points

    Hi Istvan,

    1. The 10 nV/√Hz spec is the isolated noise of the device's output circuit at a midscale code. Reference noise was removed from this measurement. The plot in Fig 6-21 is with other sources of noise present and may be for accurate for an application. I will make a note that this is unclear in the datasheet.

    2. I will see if we have any dynamic performance data for the DAC8830.

    3. We don't have noise spectrum graphs for the 0.1 - 10 Hz range. Both datasheets have 0.1 uVpp for the 0.1 - 10 Hz range, with midcode.

    Thanks,
    Lucas