UCD3138ALLCEVM150: Sizing of output DC capacitor bank

PP N

Hi,

With reference to UCD3138ALLCEVM150 schematic, there are a few SMD MLCC capacitors placed as a part of the capacitor bank.

Can you please clarify the role of these MLCC capacitors (C50, C53, C54, C55, C68) that are present in addition to the electrolytic capacitors?

If so, please put forward the specific requirement regarding selection of these MLCC capacitors at the output side?

Thanks,

Pratik

0 Xuemei Lu over 2 years ago

Hello Pratik,

Those capacitors are behaved as high frequency filter. As for the selection, it depends on your requirement on the output ripple.

Best Regards,

Xuemei

0 PP N over 2 years ago in reply to Xuemei Lu

Please clarify whether it depends on output voltage ripple or ac current ripple of dc bus capacitors?

I just a wanted a bit of clarity because output electrolytic capacitors are present as well. Please justify the presence of these MLCC capacitors.

+1 Xuemei Lu over 2 years ago in reply to PP N

Hello Pratik,

It's the output voltage ripple. There may be high frequency ripples with the absence of those capacitors.

Best Regards,

Xuemei

0 PP N over 2 years ago in reply to Xuemei Lu

Thanks Xuemei for your support.

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