Schematic specifying polarised caps at uncommon value.

Hello there.

I am looking at the following two datasheets:

http://www.farnell.com/datasheets/2050065.pdf http://www.farnell.com/datasheets/2050085.pdf

The application circuit for the first component asks for a 4.7uF polarised cap, which I am assuming to simply be an electrolytic cap.

The application circuit for the second component asks for a 0.1uF polarised cap - again assuming to be an electrolytic cap. What I'm finding strange is that there aren't a great deal of elec. caps of this capacitance compared to MLCCs.

Is there any justification for either of these components to be specifying polarised caps, or would ceramic caps be just as suitable? If so, why use a symbol for polarised caps?

Thank you.

The 0.1uF doesn't have to be polarized.

The datasheet does show polarized. A quick search for 0.1uF Electrolyic in Digi-Key showed 343 results starting at $0.04 each 4.7uF is a standard size also. You could use just about any type for these, they’re just there for some noise filtering.

0.1 µF in a low voltage would usually be a Tantalum.

I suspect the circuit diagram was copied from another datasheet without thought. This is a non-critical capacitor, use what you like, try it without as its optional.

Paul__B: 0.1 µF in a low voltage would usually be a Tantalum.

A Tentalum is polarized.

A quick search for 0.1uF Electrolyic in Digi-Key showed 343 results

Ah, I was using farnell.co.uk which provided just over half a dozen!

Thank you everybody for your help. :)

SteveMann: A Tentalum is polarized.

And your point is? :blush:

I guess you are aware that those 2 tsop devices are completely different. One filters out the carrier signal, giving interpreted data. The other does not, leaving you to identify the start and end of the carrier bursts.