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TPS4811-Q1: Output capacitor

Part Number: TPS4811-Q1


We use TPS48111-Q1 to provide power to an external pump (which is supposed to be an inductive load).

During the power-up the pump behaves very strange. It consumes a lot of current causing DC/DC supplying the power to shut-down and up.

After adding 220nF capacitor at the output, the pump "calms down" and everything works good. The original design doesn't have output capacitor at all.

However some pumps still makes trouble, but after increasing the output capacitor to 1uF, they start working good.

At the previous version of datasheet there was recommendation to add a minimum of 22nF from SRC to GND, however this recommendation is not present in a new datasheet:

Is there any recommendation to use an output capacitor.

If so, how can I calculate its value?



  • Hi Alex,

    The output capacitor requirement is purely driven by the load needs and has nothing to do with TPS4811-Q1. So, check with the pump manufacturer for their recommendations on the capacitance

    What is the load current of pump? 

    Can you share your TPS4811-Q1 schematic for review.

    Best Regards,