What if I use tantalum instead of aluminum capacitor

[e.koc]

Hi,

I am trying to build a power circuit arround a DC/DC buck controller.There is a 470uF aluminum capacitor on the output and its too big for my design. Does it make any difference if I use two 220uF tantalum caps instead? (missing 30uF is not important)

Thanks for any help.

Emin

 

[keith1200rs]

Yes, two Tantalums will be fine (but not as cheap as aluminium).

Keith

 

[e.koc]

Thanks for responding. I forgot to say that the output must be very stable (1.0V with %5 accuracy). You said fine. Even in this case, can there be any problem?

 

[keith1200rs]

The differences between tantalum and aluminium is that tantalums have a lower ESR and better high frequency response. For that reason they are normally used in place of aluminium for critical applications, such as switching regulators. So, using tantalum in place of aluminium is usually not a problem - the other way round could be. In fact, if it is for the output of a switching regulator I am surprised it isn't tantalum anyway (or maybe ceramic). The worse high frequency response of aluminium tends to mean more high frequency ripple than if you use tantalum.

Keith.

 

[e.koc]

I was suprised too and I wanted to ask because I suspected that maybe I was missing something and it might be important to use 470uF cap in one piece.
I'll try tantalums. Thank you Keith.