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TPS7A52-Q1: Input and Output capacitors

Part Number: TPS7A52-Q1

Hello,

I have a question about input and output capacitor requierements. Datasheet says "The TPS7A52-Q1 is designed and characterized for operation with ceramic capacitors of 22 μF or greater (10 μF
or greater of capacitance) at the output and 10 μF or greater (5 μF or greater of capacitance) at the input. Use at
least a 22-μF capacitor at the input to minimize input impedance."

- For the input is 10uF OK like first sentence explains or we need 22uF?

- What is the sense of "10 μF or greater (5 μF or greater of capacitance)"

Thanks

Regards

  • Hi,

    1. The actual capacitance of a given capacitor will often be less than its nominal value depending on the temperature and DC bias. Since the TPS7A52-Q1 requires at least 10 uF on the output after accounting for this derating, using a 10 uF will not be enough to ensure stability and reliable operation. It is recommended to use an X5R or X7R ceramic output capacitor with a nominal value of at least 22 uF to ensure that the 10 uF minimum capacitance is met over the full operating temperature and DC bias conditions.

    2. Similar to the output capacitance, the input capacitance must be at least 5 uF after accounting for temperature and DC bias derating. TI recommends using a capacitor rated for 10 uF to ensure this design requirement is met.

    The Murata SimSurfing tool includes DC Bias and Temperature characteristics for many of their capacitors:

    https://ds.murata.co.jp/simsurfing/mlcc.html?lcid=en-us#

    Below is an example for one of their 10 uF, 25 V, X7R ceramic capacitors:

    Please see Wilson's blog on this topic for more information:


    Thanks,

    Gerard