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VCA821: Is there noise reduction at Vg pin

Shinichi Inoue
Guru 21566 points
Part Number: VCA821

Tool/software:

Dear Specialists,

My customer is considering VCA821 and has a question.

I would be grateful if you could advise.

---

In the case of analog VGA, the output voltage may fluctuate greatly due to noise in the gain adjustment voltage.

In the case of VCA821, can noise at VG pin be reduced internally?

Or does the noise applied to the VG pin directly affect the gain?

In this case, the control voltage must be kept very clean.

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I appreciate your great help in advance.

Best regards,

Shinichi

  • +1
    TI__Mastermind 22494 points

    Hello Inoue-san,

    If the noise is within the bandwidth of the pin, the noise would cause a change in gain.  This VG gain control pin is an analog pin, with a continuously variable gain.

    Is there a specific type of noise or expected noise the customer is concerned about?  Generally a nV or mV noise signal would not change the gain as much as a larger voltage change, but there will be an affect.  A clean or consistent signal would be recommended for VG.

    Best,

    Alec

  • 0 in reply to Alec Saebeler
    Guru 21566 points

    Hi Alec,

    Thank you for your reply.

    I understand there is no filter in the VG pin.

    It is recommended that the signal input to the VG be suppressed so that noise is less than a few mV.

    I'll share this information with the customer.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi