MPM3810 Ouput Voltage Ripples (non-constant voltage)

DC-DC Power Converters
1

Hello!

I use MPM3810GQB (Adjustable) as 3,3 V voltage source. Vin is 5 V.
I see ripples about 250 mV (please check diagram below) when no load. Is it OK?

20221112_161246
20221112_1612461920×1440 279 KB

Thanks for answer.
With regards,
Maksim

2

Hi ,
Thank you for utilizing MPS Technical Forum,

The output ripple of 250mV seems quite high, it should be much lower, around 30mV or so.

Can you please provide me the output capacitance you are using?

Also - one place to look into for output ripple characteristics and compare - is the waveform listed in the datasheet. Refer to capture below:

image

Kind Regards,
Nouman

3

Hi @MPSnow_Nouman
I use 470 uF x 16 V electrolithic capacitor and 0.1 uF ceramic capacitor.
Ripples becomes much low after I added 47 uF tantalum capacitor.

What is the preferred capacitor type combination to be used with MPM3810?

Thanks for answer.
With regards,
Maksim

4

Hi Maksim,
You can use the 47uF tantalum capacitor with an additional ceramic capacitor of low value like 1uF or .1uF to lower the ESR. Put the Tantalum cap and ceramic capacitor in parallel on the output rail.

The combination is of capacitor are different per application. Typically, lowering ESR resistance by adding a ceramic capacitor helps lower the voltage ripple.

Best Regards,
Nouman