tantalum caps wasRe: emc success

--- In CAD_CAM_EDM_DRO@egroups.com, ballendo@y... wrote:

> Mariss writes:
> >Tantalum capacitors blow up very readily due to their very low
> >internal resistance (ESR).<snip>
>
> Mariss,
>
> Do you agree with Jon E that their(tantalum caps) use should be
> avoided ?
>
> Ballendo

Hi,

Not at all. Tantalum caps feature very low leakage currents and tight
tolerance, making them the prefered choice for timing circuits. Their
low ESR and inductance also make them suitable for high freq
bypassing. I do however consider them a "fragile" component because
their low ESR permits single pulse currents that are destructive.
That is not the case with Al 'lytics and multilayer ceramics. Ceramic
caps also have low ESR and inductance but tolerate without harm
current pulses that would immediately destroy tantalum caps.

Improvements in multilayer ceramic caps coupled with the recent
tantalum powder shortage has made ceramic caps an attractive
alternative.

I should know; originally the G201 and G320 were specified with 1206
case size tantalums (4.7uF/16V). When the price rose from $0.15 to
$1.25 per cap in 10K quantities, something had to be done. We tested
and qualified multilayer ceramic caps, same case size and ratings.
The price in similar quantities is less the what the tantalums
originally cost.

Their only drawback is the +80% -20% tolerance over temperature for
the Y5V dielectric, making them unsuitable for precision timing
circuits.

Mariss