Re: standard size for smt tantalums?

Hi Michael,

> Hi - I was just wondering - I've noticed that there are very few
> tantalums made in the standard discrete surface mount sizes (1206,
> 0805, etc.). I was able to find a very limited selection of such
They have standard-sizes. Only the smallest fits a 1206 pad. (in
millimeters:
1.2 x 0.1 inch = 3.05mm, 0.6 x 0.1 inch = 1.53mm so an 1206 equals
a (non-existing) 3116 sized tantalum...)
The sizes are coded A or in Numbers 3216 (which means 3.2mm x 1.6mm),
B (3228), C (6032), D (7343) and E (same as D but greater hight).
Sometimes additional sizes are available (depending on the
Manufacturer.
Check out AVX, Murata, TDK
e.g. http://www.avx.com/docs/catalogs/taj.pdf

> capacitors made by TAC (for example, Digi-Key part # 478-2562-1-ND).
> But these are expensive (over $2 each for an 0805 in quantites of
> 100, compared to $.50 for similarly specced tantalums in different
> packages). So my question is this: Are there standard sizes for
> tantalums? Or does each manufacturer have their own sizes?
As others alredy mentioned... these might be ceramic caps.

> As long as I'm on the topic of tantalums - can somebody tell me why
> they are reccomended for power smoothing? Would a ceramic work just
> as well? (as they're cheaper and available in sizes I'm more used to)
Ceramics work much better (lower ESR, long-term stability) but are
much more expensive (you mentioned $2 each).
Many (not cost-sensitive) designers prefer to use ceramics, since they
are much more reliable than tantalums.

cu
Bernhard Spitzer
--
bash.org - Top 100...
<erno> hm. I've lost a machine.. literally _lost_. it responds to ping, it
works completely, I just can't figure out where in my apartment it is.



.

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