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TPS43351-Q1: Power management forum

Part Number: TPS43351-Q1

TPS43351 outputs 3.3.v/2A, of which C533 C536 is tantalum capacitor and C35 C34 C38 37 is ceramic. At present, in order to reduce the cost of the project,

is this side of the capacitor not needed so much, redundant,

and is it necessary to use tantalum capacitor, is there any good suggestion or capacitor brand recommendation?

  • Hello,

    The output capacitor determines the output voltage undershoot and overshoot during load step according to this formula:

    Delta (VOUT) = (1/2)*(0.35/Fc)*delta (IOUT)* (1/C0). Where:

    Delta (VOUT) is the output voltage undershoot or overshoot

    Fc is the loop cross over frequency

    Delta (IOUT) is the load current step

    C0 is the total output capacitor

    Example: delta (VOUT) = 20mV at 1A load step, and cross over frequency 50KHz, the calculated output capacitor is 175uF. That means 2 x 47uF ceramic and 100uF tantalum can be used.

    With the actual capacitor the voltage ripple is around 10mV at 50Khz cross over frequency.