Re: standard size for smt tantalums?

On Mon, 04 Jul 2005 22:35:07 -0500, Michael Noone
<mnoone.uiuc.edu@xxxxxxxxx> wrote:

>John Larkin <jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in
>news:0kojc1tvbu83ttbp263s8rqfplq6u5i7s7@xxxxxxx:
>>
>> You can now get a 100 uF 1206 ceramic, but they have rotten tc's and
>> voltage/capacitance coefficients.
>>
>> There are five or six standard surfmount tantalum sizes. DON'T use
>> them for power supply bypasses; they tend to detonate. The new polymer
>> tantalums are OK.
>>
>> John
>>
>So for power supply bypassing I should use polymer tantalums? Or is there
>something better than that? I should mention that size is a bit of a
>constraing here... The smaller the parts I can use the better! I was
>looking on the Digi-Key catalog and found a couple different series' of
>surface mount polymer tantalums:
>
>Kemet: (Digi-Key page 970: http://dkc3.digikey.com/PDF/T052/0970.pdf)
>T520 Series - KO-CAP Polymer Tantalum
>T525 Series - KO-CAP Polymer Tantalum
>T530 Series - KO-MAT Polymer Tantalum
>
>Epcos: (Digi-Key page 976: http://dkc3.digikey.com/PDF/T052/0976.pdf)
>B45294R & B45296R Polymer Ultra-Low ESR Series
>B45496R Polymer Multiple Anode Ultra-Low ESR Series
>
>Do any of these look like good choices for power supply bypass? (or any
>others that I missed - though I looked fairly carefully)
>

How about aluminum electrolytics? Since they're tall, you get at least
as much capacitance per pcb footprint as you do with tantalums.

John

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