> Hmm, I was  under the impression that tantalum was 
> lower ESR than
> electrolytic and i've seen datasheets specify 
> "ceramic or tantalum"
> which reinforces this view. But the table in that 
> article puts tantalum
> as a higher ESR than electrolytic.
>
> Can anyone clarify? was I wrong? is this something 
> that has changed with
> recent technical developments?

Peter,

Never rely on a "generalized" table.  Tantalum caps can 
have extremely low ESR, depending on the manufacturer 
and series.  Some have internal fuses in series which 
raises the ESR (and negates the reason for using tants 
in the first place). You must read / understand / 
interpret the spec sheets for all parts in order to 
choose correctly. Manufacturers typically are poor at 
rating their caps, especially for items such as 
temperature rise and ripple current. All of the above 
being said, E-Caps typically have highest ESR (violent 
hand waving now in progress). Large value (multi-uF) 
ceramic caps have gotten much cheaper in recent years, 
have decent ESR and are often preferred over tantalums 
for various reasons.

Ken

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