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VCA824: about the linearity of the VCA824 gain

Chu Allen
Intellectual 830 points
Part Number: VCA824

Tool/software:

Hello,

I would like to inquire about the linearity of the gain of VCA824. Through simulation and actual testing, I have found that the relationship curve between the gain and control voltage of VCA824 is not perfectly linear as shown in the manual.


This is the waveform of the relationship between gain and control voltage when simulating a fixed Vin (100mV) and Vg varying from -1~1V, showing visible nonlinearity.

I want to confirm with TI whether the manual describes the ideal results or if the linearity is poor due to deviations in my designed circuit?

  • 0
    TI__Intellectual 2700 points

    Hi Chu,

    For any VGA, there can be three type error in the gain plot,

    1. offset error which is the DC shift in the gain plot

    2. Gain error - deviation in the slope of the gain plot 

    3. Conformity error - this is the deviation from the linearity in the gain plot.

    The combined error from all the three should not exceed the maximum number quoted in the Gain error / gain deviation section of the electrical characteristic of the device's datasheet. And this is guranteed number.

    So can you please check if error whihc you are getting in gain for the entire range of Vg is more than this number or withing the datasheet's max number?

    Regards

    Anant