Dan, Robert has provided a summary. It boils down to basic engineering.
Know your environment and know the device characteristics. I have'nt had
a Tantalum cap fail in decades. There is a good reason they are specified
in vendor's application notes. If you use a 6V Tantalum in a 5V supply of
questionable design, you are asking for trouble. This topic has come up
before and there are those folks that think Tantalums are `evil'. I've
seen far more problems with electrolytics in hot environments and they
can be much more `explosive'...

   - Tom

PSBS: I had more to say on the LTC2400 and Dennis' comments about
`Think before you comment' and "Bit Jittering" which I assume meant
"Dithering" which I don't think is practical at the sub uV level but
I've been busy and I'll try to follow up...

At 12:19 AM 4/28/00 -0600, Dan Michaels
 wrote:
>Robert Wuest wrote:
>>> ......
>>Most applications of Ta caps that I have seen are OK.  Most power supply
>>circuits cannot provide the high amp surges required for this to be a
>>really significant issue and most Ta caps don't blow up :)
>.....
>>If the power supply can provide mucho current, you should place some
>>sort of inrush current limiting (like an NTC device) in series.  On a
>>linear supply, put it before the regulator. Also, you can use a higher
>>voltage rated part because they can take more inrush.
>>
>>Actually performance specs are hard to get, but 1 ohm source impedance
>>can blow parts.  So for a 5 Volt supply that provides 5 amps max (and
>>say a 6 volt cap), you're on thin ice.  2 ohms is safer.  Or use a 10
>>volt cap.
>>
>
>Great, Robert, thanks for the straight scoop. This last sounds like
>a good rule of thumb. It looks like the big dogs like Wagner and Grif,
>with their 5A to 200A supplies, better keep their helmets on, but us
>little dogs with stuff running off wall warts can rest easy.
>
>Also, as someone else mentioned, ie PaulB, there are a couple of
>different types of tantalums. Can we treat them the same, viz-a-viz
>this "low-impedance" blow-up-in-your-face issue?
>
>best regards,
>- Dan Michaels


------------------------------------------------------------------------
Tom Handley
New Age Communications
Since '75 before "New Age" and no one around here is waiting for UFOs ;-)