MPM3695-10 output voltage ripple issue

Integrated Inductor Power Modules
1

I am using MPM3695GMQ-10-0022 IC in my design. But for one of the output voltage (3.5V) the output show high magnitude of ripple occurring at low frequency ~25Hz at no load. See the image.

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-Input voltage is 5V stable supply
-No programming done to IC, default only present
-External feedback resistors 17.4K(upper) and 3.6K(lower) use to derive 3.5V.
-input cap used : 22uF
-output cap used : 3 x 22uF to support 4A of load current

Same converter is used to derive 2V output with external feedback resistors for that no such issue is happening. Even for 3.5V output if we change the feedback corresponding to 2 V output become stable.

Please help on this why such high magnitude very low frequency ripple occurring for 3.5V output at no load.

2

Hello Ankur,

May you please explain how you are measuring the output? We recommend using a spring ground probe tip or a very short ground loop on your probe to minimize noise pickup. Measurement point should be made directly on the output capacitors as well. Are you also using full bandwidth on your oscilloscope?

You may also further contact the MPSNOW team at mpsnow@monolithicpower.com if you would like to deep dive into the smaller details.