• State
  • Locked Locked
  • Replies 6 replies
  • Subscribers 47 subscribers
  • Views 433 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.

I need a high-speed DAC with very low residual 1/f phase noise

Electron-Whisperer
Prodigy 30 points
Other Parts Discussed in Thread: DAC3484, DAC5688, DAC5681, DAC34H84

Hi,

I need a high-speed DAC with very low residual 1/f phase noise.

Maximum clock rate should be at least 200MHz, 400MHz or higher would be nice.

Resolution should be at least 14-bit, 16-bit preferred.

Data interface should be LVDS or CMOS. DDR interface is OK if it can transfer one data sample per clock cycle. JESD204B is kind of OK if it is able to run with 40MHz DAC clock frequency.

Residual phase noise (assuming a noise-free clock signal and supplies run from virtually noise-free batteries) at 100Hz fourrier frequency and 20MHz output frequency should not be higher than -150dBc/Hz.

Is there anything from TI that would match these requirements?

Thanks,
Whisp

  • 0
    TI__Mastermind 20541 points

    Hi Whisp,

    DAC5671, DAC5681, DAC5688, DAC3484, are some of the device will meet requirements. 

    Regards,

    Neeraj

  • 0 in reply to Neeraj Gill
    Prodigy 30 points

    Hi Neeraj,

    Where can I see the close-in phase noise of these DACs?

    Regards,
    Whisp

  • 0 in reply to Neeraj Gill
    Prodigy 30 points

    Is the DAC3484 comparable to the DAC34H84 (what exactly is the difference between these two)?

    Because the DAC34H84 seems to have a phase noise of -132dBc/Hz at 100Hz offset when outputting 30MHz (reading at -130 in the graph, but it seems to be rather -132 when extrapolated from 1kHz and 10kHz values, assuming there is something else causing the deviation from the 1/f law below 300Hz), which would result in -135.5dBc/Hz at 20MHz. This value is from a PowerPoint presentation comparing the effect of power supplies (HP6216A vs. E3631A).

    So unless the HP6216A would still be worsening the DAC's noise a lot, I would need a DAC with a much lower residual phase noise.

    It really would be nice if there was a table comparing the residual flicker noise characteristics of available DACs.

    As flicker noise is always 10dB per decade with regard to offset frequency, one could extrapolate it to 1Hz offset frequency and as it almost always 20dB per decade output frequency it could be scaled to a convenient output frequency like 1MHz.

    Scaled to 1Hz Offset and 1MHz output frequency, this would put my requirements at -156dBc/HZ (150dBc +20dB from 100Hz offset to 1Hz and -26dB from 20MHz output to 1MHz) and the DAC34H84 at -141.5 (-142dBc +30dB from 1kHz offset to 1Hz and -29.5dB from 30MHz output to 1MHz).

    Regards,
    Whisp

  • 0 in reply to Electron-Whisperer
    TI__Intellectual 1950 points

    Hi Whisp,

    They are different packages and DAC34H84 has more lanes. I will work on getting the measurement for you, please give me a couple of days to get this for you.

  • 0 in reply to Miguel Lomeli
    Prodigy 30 points

    Thanks for your offer, but if they only differ with respect to the package and lane counts, you would not need to measure the performance, as this surely won't bring the 15dB improvement I would need.

    AFAIK the phase noise performance depends on the path from the DAC clock input to the latches directly before the current steering switches, the performance of these latches and on the current steering switches and the according current sources.

    Is there any compilation of TI DAC phase noise measurements, other than just the wideband noise floor?

  • 0 in reply to Electron-Whisperer
    TI__Intellectual 1950 points

    Hi Whisp,

    Have a look at our latest DAC https://www.ti.com/lit/ds/symlink/dac12dl3200.pdf. In the Electrical Characteristics there are phase noise measurements