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TPS7B63-Q1: Enough actual capacitance of input/output capacitor

RYO
Intellectual 2000 points
Part Number: TPS7B63-Q1

Hello all,

I would like to know the enough actual capacitance of input/output capacitor when using TPS7B63-Q1.

In the datasheet of this device, the recommended input capacitor range is 10uF-22uF and also 0.1-uF ceramic bypass should be placed. I think this is because of the actual capacitance can be changed due to DC bias, temperature, variation of initial capacitance, and also the frequency of noise. I would like to know the recommended actual input and also output capacitance when DC. The other condition is indicated below:

  • Input voltage: 8V-16V
  • Output range: 4.5-5.5V
  • Output current: 100mA
  • Temperature: -40 to 100degC

Thank you,
RYO

  • 0
    Guru 140200 points
    Hi Ryo,

    section 9 of datssheet goes into more detail. The >10µF + 100n ceramic input capacitors is what you must have if the input supply is located more than a few inches from the TPS7B63xx-Q1.

    Take this recommendation seriously. LDOs urgently need proper decoupling caps at input and output for stabilty!

    Kai
  • 0 in reply to kai klaas69
    TI__Expert 4435 points
    Hi Ryo,

    TI's Linear Regulator datasheets show the recommended minimum capacitor value. You can buy this capacitor and use it with the Linear Regulator and it will meet the datasheet performance specs and will be stable. When choosing a minimum value for the datasheet, we factor in margin to account for effective capacitance due to initial tolerance, DC bias, temperature, etc.

    The output capacitor affects the Linear Regulator's stability. Figure 14 shows that an output capacitor in the range of 4.7 μF to 500 μF will guarantee stability.

    The input capacitor is required to provide a known impedance on the input of the linear regulator. Input cap can affect dynamic performance and all design simulations assume a minimum capacitance on the input. The recommended input capacitor for this device is 10 μF - 22 μF with an additional 0.1 μF.

    You can buy and use the recommended capacitor values and not have to further assess effective capacitance.