: cc:
owner-emc-pstc@majordoSubject: Re: Tantalum
Capacitor Reliability
mo.ieee.org
Chris,
You may want to look at some of the "polymer aluminum electrolytic"
capacitors from:
* Cornell Dubilier.
* Elna.
* Jaro Components.
* Kemet.
* Matsushita.
* NIC Components Corporation.
* Nichicon.
* Panasonic.
* Samchung.
* SDK.
* etc.
I've used them on the last two controller c
Chris,
I've had this same problem over the years with many man hours spent looking
for why. We changed to 35 and 50 V parts to good effect in some cases.
Other cases were not so easy. I like Cortland's idea the problem is charge
current at turn-on. We had a 5 output 350 watt supply and there
On Mon, 29 Jul 2002 15:41:32 -0400,
"Chris Maxwell" wrote:
> One of my colleagues is testing a new design. He has designed a
> buck-boost switching converter which has tantalum output capacitors.
> We have looked at his design and gone through the calculations. His
> output current is 4 A ma
When we started seeing 50 volt caps blowing up on a 5 volt output it became
evident that the problem _we_ had, "instant mortality" (grin), was
over-current, not over-voltage. We didn't actually see a voltage transient
- a 'scope had in fact ruled that out - but someone in management had
apparentl
Been a while, but the voices from a former life in my
head are reminding me of something to the effect that
rated ripple current of cap is based on a perfect sine
wave of ripple. Any other type of waveform can
drastically effect that rating.
SuperLo ESR caps were used one time to solve such
ients on Line-Connected Capacitors, NASA/CR-2000-209906, NASA Marshall
Space Flight Center, AL 35812, February 2000, pp. 33.
and it can be found at:
http://see.msfc.nasa.gov/see/ee/eepub.html
--
>From: "Chris Maxwell"
>To: "EMC-PSTC Internet Forum"
>Subje
Nonetheless, inrush current aside, a 20V Tantalum is considered marginal for a
12V
circuit if reliability is desired. A 60% derating factor was and is a typical
max
for reliability circuits, i.e a 30V min rated cap is recommended. Tantalums
require
additional derating than Al-electrolytics. Fur
Chris,
The issue isn't voltage rating; low-ESR caps such as these are susceptible
to excessive charging current at turn-on. At a former employer, we saw
REALLY GOOD, expensive caps used on a computer's 5V bus exploding at
turn-on, even ones rated at 50 volts. Replacing them with cheaper
electrol
Hi all,
By the way, thank you to the various group members for the responses regarding
the hazardous atmosphere classifications.
One of my colleagues is testing a new design. He has designed a buck-boost
switching converter which has tantalum output capacitors. We have looked at
his desi
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