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Original question:

TLV62569: Questions of TLV62569

TLV62569: Schematic review

Jayden Qiu
Intellectual 955 points
Part Number: TLV62569

HI team，

This is fae Jayden. My customer uses TLV62569DBVR in their new design. could you help review the schematic they just finished?

Vin=5V, Vout=3.6V, Iout=1A, Cin=3*22uF+0.1uF, Cout=3*22uF+10uF+0.1uF, L=2.2uH, cff=22pF

TLV62569 scematic.pptx

could you help check if the the phase margin and magnitude margin is enough for their design? Thanks.

 Brs

Jayden

  • 0
    TI__Prodigy 70 points

    Hi Jayden,

    the inductor/ferrite bead on the input rail forms an undamped LC filter with the input capacitors, and this can lead to input voltage overshoots.
    This filter should be damped by adding another input capacitor (5 times the value of the current input capacitance) with a series resistance.
    Regarding this, the input capacitance can be reduced, so the damping capacitor doesn't need to be too big.
    It's explained in section 4 in this application note: www.ti.com/.../slvafe0.pdf

    With this inductor, the output capacitance should not be higher than 2x22uF as recommended in the datasheet.

    Regarding the phase and gain margin, there is no easy way to determine that as we don't have a simulation model.
    But if the output capacitance is reduced to the recommended value, I see no problem with the phase and gain margin.

    Thanks,
    Maximilian