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LMR16020: Output Capacitor Recommendation

Genius 15319 points
Part Number: LMR16020
Other Parts Discussed in Thread: LM5012

Hi Experts,

Seeking your assistance on this query:

We want a 24V 2A DC-DC switching regulator with wide input range of about 30 to 55V. I choose LMR16020PDDA, but we want you to clarify us in choosing the correct output capacitor.

I modelled the circuit in TI's Webench power designer, but there was no part number suggested for output capacitance, could you help me in choosing the correct part? (Webench Design Attached)

We plan to use the same part for both 24V/2A and 28V/2A as well. Kindly suggest us the output capacitor for both designs.

Regards,
Archie A.

  • Upon checking from its EVM, I could see combinations of output capacitors from BOM's list. And I believe that the customer would just need combinations of such type added together to come up with ~125.804uF or higher. Wanted to make sure from an expert to find such OPNs from any of our authorized distributors.

    For your confirmation please.

    Thanks ahead,
    Archie A.

  • Hello Archie,

    We advice ceramics to be considered for output capacitor. The preferred dielectric, especially if the application sees a wide range of temperature would be X7R.

    Customers can also consider a low ESR (<50mohm) electrolytic capacitor if they prefer that.

    If considering an electrolytic capacitor, it would be best to model the ESR  in webench as this would constitute an additional zero in the loop. This in combination with the feedforward capacitor's zero already implemented in the design could cause a high crossover, being non ideal for our internally compensated regulator.

    Furthermore, the customer may want to consider LM5012 with it being a newer device and potentially having less supply constraints.