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Fast DAC converter DAC3484 sampling rate for each channel

Liang Geng
Prodigy 80 points
Other Parts Discussed in Thread: DAC3484, DAC5681, DAC34H84, DAC5682Z

Hi.

I am looking for a fast DAC converter (>1Gsps) for my FPGA based communication system design.Unfortunately after I got the DAC3484EVM, I found this might not fit my application.

 

If I am correct, the DAC3484 has a maximum sample rate of 1.25 Gsps at the digital input end. But for each of the 4 output channel DAC, the sampled digital input actually has a maximum rate of 1.25G/4=312.5Msps. Is this correct?

In my case. I only need one channel and the signal generated from the FPGA has an minimum sampling rate of 800MHz, which mean I will need an 800Msps DAC. Could you suggest which module I should look at? I found DAC5681, would that suit?

And just a bit of interest, for the multichannel DAC chips you have, the DAC module for each channel actually has a sampling rate of 1/n of the input sampling rate (n channels). is that correct?

  • 0
    TI__Guru* 78374 points

    Hi Liang,

    Yes, you are correct. Due to the interleaving 16-bit input data format, the maximum data rate per DAC is limited to 312.5MSPS for the DAC3484. In order to support 800MSPS per DAC, the DAC5681 is the only choice so far. You may also want to look into the DAC5670.

    Liang Geng said:
    And just a bit of interest, for the multichannel DAC chips you have, the DAC module for each channel actually has a sampling rate of 1/n of the input sampling rate (n channels). is that correct?

    This is not necessary true. For instance, our DAC34H84 has 32bit of LVDS input, and this allows the maximum data rate per channel to be 625MSPS. The input data rate will depend on the input data format.

    -Kang

  • 0 in reply to Kang Hsia
    Prodigy 80 points

    Hi Kang,

    Thank you for your reply.

    I have been looking into DAC5681 and DAC5682 series. I found that 5682, though dual channel, allow single channel mode. Am I right that saying 5682 in the single channel mode is taking the input data purely to one channel therefore give an 1Gsps conversion just like 5681 (say all in 1x interpolation mode)?

    If this is the case, I think I am going after DAC5682z.

    Best wishes,

    Liang

     

     

  • 0 in reply to Liang Geng
    TI__Guru* 78374 points

    Hello Liang,

    The DAC5682z does have the 1x1 mode that is the same as the DAC5681. If the cost is not a concern and you need the flexibility to switch back to dual DAC mode, then the DAC5682z may be a good choice. 

    -KH