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TPS54620: When input / output capacitors are connected in parallel.

Part Number: TPS54620

Hi team.

My customer has inquired about multiple Input/Output capacitors connected in parallel.

Please tell us what problems you may encounter if you use several capacitors with low capacitance instead of one capacitor with high capacitance.

Customers have problems with supply of large size capacitors(MLCC).

For example, two 3216size 100uF capacitors were used for voltage output.

The customer is trying to set this output capacitance to using 1608size 10uF x 20ea.

1. Is there any problem when using several small size capacitors as above?

TI's EVMs have large size and large value capacitors in most cases.

2.  Do you have the information you have tested using multiple small size and small value capacitors in parallel?

Thank you.

  • Charles,

    Generally speaking it is ok to  use multiple MLCC in parallel.  We do it often.  In your specific example it may be impractical to use 20 capacitors in parallel due to routing and placement.  Typically you want to keep the circulating current loops small for the input and output.  This is especially important on the input.  Input capacitors located away from the input pins are not very effective.  For the output, it is less critical.  Can they use 8 or 10 22 uF?  That should be able to be placed and routed in an effective manner.  Can you show me the proposed layout for 20 x 10 uF?

  • Dear John.

    The above problem has been solved.

    However, there are additional questions you should ask about customer circuit.

    May I ask you by e-mail?

    Thank you