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Original question:

VCA810: VCA810

VCA810: Linear TVG

Pete Sampson
Intellectual 440 points
Part Number: VCA810


Tool/software:

Are there app notes or reccomended circuits for using an ampifier like the VCA810 to apply a linear or logoroithmic TVG for a ~40khz signal (or higher freq) across temperature without having to wake up an MCU? Or, is there a way to have the MCU program in gain response curve on startup but not have to repeat that unless it decides to be updated (this would be ideal)? The goal is apply a TVG without waking a MCU which is many ways similar to AGC but the problem with AGC (I suspect) is that it will normalize small ampitude changes reducing the effectiveness of ampitude based object detection.

  • 0
    TI__Mastermind 31025 points

    Hello Pete,

      If the MCU is being used to control the Vg (gain control) of the device, then I am unsure if that is possible unless you are able to use a different method to control the Vg. There isn't a way to program the VCA810 on startup, since the device reacts to the Vg set at the time of measurement. Unless are you referring to the MCU programing running a program on a loop with a certain response to apply at Vg. That would work if you know beforehand the temperature changes.

       Another idea would be if you can use a thermal resistor between MCU analog output to VGA, and then this thermal resistor (thermistors) would change the set potential provided by MCU by increasing/decreasing in resistance value with varying temperatures. 

    Thank you,
    Sima