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DAC38RF80: how to control gain of DAC38RF80

Aiden Lee
Prodigy 20 points
Part Number: DAC38RF80

I will use DAC38RF80 for my project.

I read (8.3.19), (8.5.39) and (8.5.40) on dac38rf80.pdf, so I have a few question.

I want to know the maximum and minimum gain values when I control these registers.

In Table56, when asserted MIXERAB_GAIN and MIXERCD_GAIN, the output power adds 6dB of gain.

Is it correct?

Does this register add gain separately from the setting of GAINAB and GAINCD?

And, how to get GUI of DAC38RF80 EVM?

 

  • 0
    TI__Guru 66014 points

    Hi, 

    the minimum gain value is 0, which maximum up to 2x (6dB)

    GUI location shown below

    These gains are different than the MXIERAB_GAIN and MIXERCD_GAIN, which is located at the output of the NCO to compensate mixing arithmetic. MIXERGAIN can only enabled by 6dB, on/off.

  • 0
    Prodigy 20 points

    Hi Kang Hsia,

    If I MIXERAB_GAIN and MIXERCD_GAIN set to enable and adjust GAINAB and GAINCD register, does it mean that gain is adjusted from 0 to 12dB?

    For your information, I will use MIXER mode.

    And I have a question.

    According to the datasheet, this DAC are capable of synthesizing wideband signals from 0 to 4.5GHz.

    Is there any problem with generating this DAC output less than 100MHz?

  • 0 in reply to Aiden Lee
    TI__Guru 66014 points

    Hi,

    Aiden Lee said:

    If I MIXERAB_GAIN and MIXERCD_GAIN set to enable and adjust GAINAB and GAINCD register, does it mean that gain is adjusted from 0 to 12dB?

    For your information, I will use MIXER mode.

    Mixer by default will have arithmetic loss. The mixergain can compensate it. You can work out the complex mixing equation for detail. You will have to be careful of digital saturation and back-off data accordingly.

    Aiden Lee said:
    Is there any problem with generating this DAC output less than 100MHz?

    You will need to find a low frequency balun to work at the low frequency accordingly.