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DAC3283: Spurious components coming out of the DAC 3283

Ravi Kanth
Prodigy 130 points
Part Number: DAC3283


I am able to generate 37MHz out of the DAC 3283, but it is also having the spurious components at 1MHz and 2MHz distance away from the 37MHz.

DAC output : 37 MHz   -5.42dBm

Spurious components at -57dBm

DAC frequency 192MHz

DATA frequency 192MHz

DDS system frequency in the FPGA -192MHz, DDS output frequency 37MHz

Interpolation 2X

DAC channel B is powered down.

Please guide me how to reduce the spurious frequency components

Thanks in advance

  • 0
    TI__Guru* 91947 points

    Ravi,

    Note that care should be taken not to exceed the compliance voltages at node IOUT1 and IOUT2, which would lead to increased signal distortion. Try backing off the input data amplitude from the FPGA. Make sure the rbias resistor is set correctly. For max output current, this should be set to 960 Ohm. It should not be any lower than this.

    If using a transformer, make sure the bandwidth of the part is within spec of your output frequency.

    Make sure the DAC is not reporting any errors or alarms. Run the Data Pattern Checker test that can be found in section 8.4.7 of the data sheet.

    Regards,

    Jim

  • 0 in reply to jim s
    Prodigy 130 points

    Dear Jim


                     thanks for the reply, in all the above given suggestions i have checked only data pattern checker, the interface is working. I will check the remaining parameters and will come back.

    Regards

    T Ravikanth

  • 0 in reply to jim s
    Prodigy 130 points

    I have written zeros on both channel A and channel B, ideally the spectrum should be zero when nothing is written, but some components are found in the spectrum and it was one of the crystal component output present on the board. Once the crystal was removed, the spurious components are gone.