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OPA692: OPA692 AC-coupled drive

Eli Hait54
Prodigy 240 points
Part Number: OPA692

Tool/software:

Hi,

Need to drive analog PAL video over 5 meters coaxial cable, therefore it looks like capacitive AC-coupling is required.

The question is if the OPA692 can drive the 75R coax load via large serial capacitor?

  • 0
    TI__Genius 11455 points

    Hi Eli,

    The device should have no problem with AC coupling at the output assuming the other end of the signal is properly terminated to 75ohms. However, I am unsure about the 1K resistors at the output. I am not too familiar with this configuration. As for the values of the coupling capacitors, we often recommend values significantly larger (330uF) to limit any potential discharging affects. 

    Best Regards,

    Ignacio

  • 0 in reply to Ignacio Vazquez Lam1
    Prodigy 240 points

    Thanx, Ignacio.

    I understand that amplifiers with SAG input minimize that capacitor by factor of 10?

  • 0 in reply to Eli Hait54
    TI__Genius 11455 points

    Hi Eli,

    That is the benefit of implementing some kind of sag correction circuitry. There are devices that have this functionality and use values in the same range, but I am unsure how effective the configuration shown is with SAG correction when implemented on PCB. 

    Best Regards,

    Ignacio