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OPA1632: Single-End to Differential converting

Genius 3870 points
Part Number: OPA1632

Hi there
we are using OPA1632 to convert single-ended signal to differential signals.Below is sch. note V_input is applied to Vin- pin.of hte amp..

By TI app. note SLOA054,   page10, we know from equations (11)-(15), 
Vod = Vid = 0 - V_input.
Vout+ = 1.3 + 0.5*Vid =1.3 - 0.5*V_input.
Vout- = 1.3 - 0.5*Vid =1.3 + 0.5*V_input.

For some reason I need to connect V_input to Vin+(pin.8) and connect AGND to Vin-(pin1), I think the red-marked +/- signs in above equations will be opposited. Right?

Vod = Vid = + V_input.
Vout+ = 1.3 + 0.5*Vid =1.3 + 0.5*V_input.
Vout- = 1.3 - 0.5*Vid =1.3 - 0.5*V_input.

Besides of this difference, is there any other influence on circuits performance if I do so?  Thanks!

  • Hello,

     Yes you are correct, if you interchange the input as shown below 

    your red-marked +/- signs will also change as below

    Vod = Vid = V_input.
    Vout+ = 1.3 + 0.5*Vid =1.3 + 0.5*V_input.
    Vout- = 1.3 - 0.5*Vid =1.3 - 0.5*V_input.

    Other than that it will not change any circuit performance.

    Regards

    Anant