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Original question:

LMH6702: Interfacing LMH6702 with DAC5681Z

LMH6702: VIDEO OUTPUT INTERFACE

SEEMA SHETTY
Prodigy 250 points
Part Number: LMH6702
Other Parts Discussed in Thread: DAC5681Z, THS3217, THS3215

DAC_SCH.pdf

hi,

Please confirm whether above schematic will give output of 0 V to +2.5V. Pin 2 should be connected to neg supply or ground for unipolar  positive output?

Also output has to drive two independent displays requiring +2.5v Video each . Can output of DAC be directly given to one more LMH6702 and above circuit duplicated?

DAC_IOUTA1 is one of the  outputs of DAC5681Z.

Thanks

Seema

  • 0
    Guru 47535 points
    Without analyzing what you are doing here,

    1. R63 needs to be series output 75ohm taking a 6dB matching loss to the final video load,
    2. Normally, you translate complementary DAC outputs using both sides to get better HD. You are doing single ended??
    3. Might be overkill, but a specific solution was developed for complementary DAC outputs to single ended drivers with the THS3215 and THS3217.
    4. differential output DAC to single ended has to deal with the active input impedance on the negative side input. There was an app note on this some years back I wrote - here,

    www.ti.com/.../sbaa135a.pdf

    5. And then Jim Karki also dealt with this issue, here -

    www.ti.com/.../slyt368.pdf