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TPS7A84: Question about the internal charge pump circuit

Go
Genius 4220 points
Part Number: TPS7A84

Hi,

My customer is concerned about the effect of TPS7A84/85/89 internal charge pump circuit on its input and output noise.

So I'd like to ask about the following things,

1. What is the switching frequency of  the TPS7A84/85/89 internal charge pump ?

2. Regarding the output noise voltage spec described in D/S, Does the spec take account of the effect of TPS7A84/85/89 internal charge pump circuit?

3. Is there any possibility that the input ripple voltage of TPS7A84/85/89 is increased by the effect of internal charge pump?

Thanks

Go

  • 0
    TI__Guru 50190 points

    HI Go-san,

    Let me answer your questions below:

    Please share your concerns about the Charge Pump noise.

    1. What is the switching frequency of  the TPS7A84/85/89 internal charge pump ?

    *Typically around 4MHZ.

     

    2. Regarding the output noise voltage spec described in D/S, Does the spec take account of the effect of TPS7A84/85/89 internal charge pump circuit?

    * The noise in the D/S is from 10 to 100KHz. The charge pump is running well outside this range.

    3. Is there any possibility that the input ripple voltage of TPS7A84/85/89 is increased by the effect of internal charge pump?

    *I don't believe so as this is a very low current charge pump that is created just to control the gate of the pass element.

    Thank you,