SMD Capacitor Type

computer guy

I am developing a circuit board for a project and have used 0603 and 0805 capacitors, however I am now looking at getting the boards made up and buying the parts and I can't find these capacitors in the right values/types.

I need:

0603 - 0.1uF
0603 - 0.47uF
0805 - 10uF

I can get these in ceramic, however the schematics I used for reference show polarised capacitors and ceramic capacitors aren't.

The 10uF capacitors are for the power supply (input and output of a 3.3v regulator).

The 0.1uF and 0.47uF are for the power input (VDD/VSS) of the propeller chip and a BT module respectively.

Would ceramic capacitors work in this situation? Or can someone point me in the direction of the capacitors I need?



Thanks

kwinn

Don't see any reason a ceramic would not work. Being non polarized is a plus as far as I can see. I am a bit surprised you can get a 10uF ceramic in 0805 though.

Phil Pilgrim (PhiPi)

You can always sub non-polarized caps for polarized, assuming there are no restrictions on ESR range. Be sure to check the datasheet for whichever Vreg you're using for the necessary specs.

-Phil

computer guy

Thanks guys. I will proceed with using the ceramics.

kwinn: http://www.x-on.com.au/InventoryDetails.aspx?id=1083679&s=1 (0805 10uF 10volts X5R 10%)

max72

It really depends also on the schematic editor.
For instance with Diptrace I use a Cap symbol polarized, so I have the cap polarity all around, even when not necessary.
I use a similar 10uF cap too (X7R 10uF 10V - mouser 81-GRM21BR71A106KE51)

A question about the format:
I've always used 0805 as form factor, because they are very easy to handle and solder. Moreover they fit nicely also on veroboards and perfboards.
What is your experience with 0603? I've never used them but I would like to give it a try.

Massimo

Phil Pilgrim (PhiPi)

0603's aren't that bad to work with. Mainly, you just need a good pair of non-magnetic tweezers to handle them. When soldering by hand, tin one pad, press the chip into it, and reheat, pressing it all the way into place when the solder melts, until a nice fillet forms. Then you can solder the other side without it shifting or tombstoning.

-Phil

max72

Thanks Phil,
this is the same approach I use with 0805.
Massimo

tonyp12

I used 0603 with infra toaster, it works most of the time.
But I still prefer 0805 as they are wider than tall and if I have to revork it due
to it standing up during reflow it's mush easier to put it back in place when it's a 0805.

0805 10uF
http://www.mouser.com/Search/ProductDetail.aspx?R=CC0805MKX5R5BB106virtualkey60120000virtualkey603-CC805MKX5R5BB106

kwinn

@ computer guy & tonyp12, thank you for the links.

Duane Degn

I like how the 0603 size of components fit between the 0.1" spaced holes on proto boards. I rarely purchase through hole resistors anymore even when I plan to use them on a one of a kind board.

Tracy Allen

The X5R and X7R ceramics are great, but one thing about the class 2 dielectrics is that they have a strong DC voltage dependence. So a 10µF capacitor will become 7µF at 3.3V bias, and down to 4µF at 6V bias. That is straight from the Murata data sheet for the 10µF 0805 referenced above. The detailed data sheet you can download from Murata is informative, probably more so than you'd want! In general, a larger, thicker capacitor will have better voltage characteristics than a small, thin one with the same capacitance. The ESR for ceramics is very good, especially at high frequencies, with low Z points in the 1 to 10MHz range. A tantalum capacitor on the other hand will have higher ESR than a ceramic, except at low frequencies, but very little voltage dependence. The details of impedance and other factors is the reason that designs often use a couple of types and values of capacitor in parallel. The bottom line is, build a couple of prototypes before you commit to a quantity!