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OPA693

Maria Fey
Prodigy 75 points
Other Parts Discussed in Thread: OPA693

I would like to know if I can use the OPA693, package SOT-23, instead the package SO-8 for output two video signals with Gain+2 with double power +5V and -5V.

Thanks.

Maria Fey

DSE

  • 0
    TI__Expert 3030 points

    Maria,

    The only issue should be related to thermals. The SOT23 package in the datasheet specifies 150 degC/W. The power dissipation can be roughly estimated as shown on page 21 of the datasheet. For 2 video loads the equivalent resistance is 75-ohms. Also, in general, the RMS output current for video is around 8mA/load and around 1Vrms at the amplifier output (always a function of true video signal but these get you in the ballpark).

    So Quiescent power lets say is 10V x 14.1mA = 141mW. Video power dissipation in the amp driving 2 video loads is roughly (5V - 1V)*(8mA x 2 loads) = 64mW. For a rough total of around 205mW. With 150 degC/W, the silicon temperature rise is 150x0.205 = 31 degC + Tambient.

    With Tambient = 85C, the junction temp would be 85+31 = 116 deg C. It is preferred to keep the silicon junction temperature below 130degC, but can support up to 150degC. Either way this should not be an issue.

    Cheers,

    Randy