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DAC3283EVM: DAC3283 cannot output any current

Part Number: DAC3283EVM
Other Parts Discussed in Thread: FMC-DAC-ADAPTER, , DAC3283

We are going to use DAC3283 in our product, so we brought DAC3283EVM board and one FMC-DAC-ADAPTER.

Use Xilinx standard KC705 FMC output LVDS data and clock to DAC3283.

Settings as below :

  • TXENABLE pin connect to VCC.
  • Interpolation : 2x
  • dac clock : 307.2Mhz
  • ostr clock : 19.2Mhz
  • FPGA output clock to DAC3283 : 307.2Mhz
  • FPGA output frame to DAC3283 : 19.2Mhz, one signal pulse according to datasheet
  • FPGA output data, we tested Sine waves, Squre waves, and constant value such as 0x7777, 0x3333.

Using SPI interface, we could read the temperature sensors, control CDC62005 clock frequency, and use oscilloscope to make sure all signals output to DAC3283 are valid.

But we cannot output any current, IOUTA and IOUTB seems no any signals.

We also make our own board, and the result is the same, no any current output.

So, we are confused using this DAC3283, is there any tips how to control the output?  

  • Hello Zhu Han,

    Your setup sounded like a standard Xilinx/Avnet Speedway development kit standard setup profile. The configuration above should be the default DAC3283 GUI setting and it should work directly with the Xilinx ML605 kit. I am not sure if there are difference in setup when upgrading to KC705. You will have to contact Xilinx for support.

    To test the DAC output, you may inject all ones (full-scale positive) or all zeros (full-scale negative) to the DAC. You may then turn on the Fs/4 coarse mixer of the DAC. You should be able to observe a tone at 153.6MHz. (assuming sampling rate of 614.4MSPS)

    Keep in mind the DAC output is transformer coupled. There is a bandpass behavior of the transformer from 10MHz to 500MHz, I believe. You will need to double check if your sine/square wave injections are within the bandpass range.

    There are many posts regarding the DAC3283 and the Xilinx Avnet speedway kit. Please do some search for the posts for more insight. Good luck.

    -Kang

  • Hello Kang

        Thank you so much for the reply!

        Since there is a design on ML605, it's easy for me to migrate ML605 to KC705. Could you tell me where to find download the ML605 design?

        Now we have disconnect the FR with DAC3283, we just connect 50OHM resistor of IOUTA and IOUTB direct to GND. But till now, for ones, Fs/4, Fs/2, no output. 

  • Hello Kang

        I searched the post, and find many articles about DAC3283 and ML605, I would try first, and update the status.

  • Hi Kang

         ML605 design is not provided, maybe the design is too old.

         for the default configuration, when the board is powered on

         

    • Interpolation : 2x
    • dac clock : 614.4Mhz
    • ostr clock : 38.4Mhz

          FPGA only output dataclkp/n fifo_istrp/n and datap/n to DAC3283.

         

        As you can see, dataclkp/n is 307.2Mhz, fifo_istrp 19.2Mhz.

        I also tried set datap/n to constant value, such as 0x7777.

       

       But the result is the same, IOUTA and IOUTB no current output.

  • Hi,

    The DAC3283 is current sink based DAC. You will need to connect 50ohm to 3.3V instead of ground to sink current through the resistor. 

    Please refer to following app note:

    http://www.ti.com/lit/an/slaa399/slaa399.pdf

    The ML605 design is from Avnet and you need to talk to Avnet to acquire the design file. TI does not own this. 

    You may also refer to the following Xilinx app note for detail

    https://www.xilinx.com/support/documentation/application_notes/xapp594-parallel-lvds-hs-dac-interface.pdf

    TI does not support any firmware related questions. 

  • It's the key to solve the problem

    In the past, we use only output DAC, so this time, sink DAC cannot output current to driver external resistor.

    After tie the output to VCC throught a resistor, not we can see the sine waves.

    Thanks so much for the help!