AMS1117 5.0 Voltage regulator question


I am making a stand alone Arduino project based on surface mount components. The voltage regulator is a AMS1117 5.0 voltage regulator with 9v input voltage.

I produced one before with through-hole components that used a 10uF electrolytic capacitor on the input and output of the 78L05CV voltage regulator.

What I want to know is are the electrolytic caps needed for the AMS1117 5.0 regulator or will I get away with using MLCC capacitors? I’m thinking of using two 10uF caps on both the input and output even though looking at the Datasheet, I probably don’t need them. These are the ones I am planning on using:

I have attached a pic of how I have it designed at the moment with the caps.

Maybe you could suggest any alternatives. I have read about the ZLDO1117 5.0 regulator which can use MLCC caps or Tantalums. Personally after reading about how spectacularly the tantalums fail I would rather use MLCC caps.

Many Thanks,

Brett Rogers

With the 1117 I use ceramics all the time, but really the correct answer to the question is read what the datasheet says about input and output capacitors - values, ESR and type. I use the AP1117 so a different
manufacturer and this sort of detail can vary between manufacturers.


I've decided that I'm gonna make a change to the regulator that I use.

I think I'm gonna change to the ZLDO1117 and use some MLCC caps on the input and output.


AMS1117 datasheet recommends tantalum caps.
There are other, newer regulators that explicitly mention "stable with ceramic caps" in the data sheet as it's not a given it'll work properly with ceramic instead of tantalum.

Look at the data sheet published by the voltage regulator manufacturer and follow there recommendations. If you investigate you will find regulators made by different companies with the same name sometimes recommend different caps. These parts are manufactured in huge quantities. The manufacturer does not want them coming back so they spend a lot of time and energy determining what is best for there devices. Many times there part is better then the generac but they will specify what the generac states. It is always safer to follow the manufacturer's recommendations, they know better then anybody else what there part can do, after all they make them.

In my designs (automotive background) I always use two bulk capacitors on the regulator input each of the specified size. If one fails and doesn't short nobody will know and no warranty:-)

Good Luck,

From AP1117 datasheet:

The AP1117 also requires a closely placed output capacitor as part of the device frequency compensation. As part of its improved performance over industry standard 1117, the AP1117 is suitable for use with MLCC (Multi-Layer Ceramic Chip) capacitors. A minimum output capacitor of 4.7μF ceramic X7R or 4.7μF solid tantalum is required.
Aluminum electrolytic can be used but a minimum of 47μF is required. When using Aluminum electrolytic it is still recommended to also use a 1μF MLCC in parallel. The ESR of the output capacitors must be less than 0.5Ω.

The AMS1117 has no such ability by the look of it, nor the LM1117.

No wonder the AP1117 is everywhere!