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LAN_403

rp181

Fri Jul 25 2008, 02:45AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

anyone see this?

...

Fri Jul 25 2008, 05:44AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

It sounds like a bunch of fud to me, the ps2 wasn't the first piece of electronics to use tant caps... Certainly it didn't create a large enough demand to cause the price of tantalum ore to quadruple...

I suppose that the part about kids being forced to work in the mines could be true (I can't really see any reason for it not to be, but given the amount of BS in the rest of the article who knows) but I also doubt that they were being forced to work because some random electronic gadget caused the price of a random ore to increase.

Dr. SSTC

Fri Jul 25 2008, 06:26AM

Registered Member #1407 Joined: Fri Mar 21 2008, 07:09AM
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Posts: 222

there just trying to make some publicity, there are 1000's of electronic devices that use tantulum capacitors besides PS2 Pffffft

Dr. Slack

Fri Jul 25 2008, 07:46AM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

No, it's not FUD. However, Sony are about as guilty of exploiting the Tanalum ore trade as every manufacturer and user of every mobile phone, handheld, MP3 player and laptop, which are also stuffed with the things. Developed supplies are limited, its properties are uniquely good for the above products, and the number of these being manufacturered has exploded in the last decade, creating barely sustainable demand.

I am an electronics design engineer for my sins, so I can give some of the back story as to why tantalum has been so important, and why it should start to wane, if not now, then within a few years.

The main reason is miniturisation, though the subtleties of battery power also pushes hard in the same direction. Small size means anything that can be done to improve volumetric efficiency is done. Whereas larger designs could use aluminium electrolytics, tantalum offers several times the uF per litre, so are the choice for hand held items. Batteries mean low voltage, hence low dropout (LDO) regulators with PNP pass elements. Older designs of LDO regulators have stability problems that require a certain range of ESR for their output capacitors. This means that ali or tant would do, but even as the newer high K ceramics were becoming available in the last decade, they have had too low an ESR for LDO use, which oscillated. Thus tantalums were pretty much mandated for LDO use, and much preferred everywhere else. Once they were on the board, they tended to get used everywhere for values > 1uF, even if ali or ceramic could have fitted, as the economics of manufacture requires large quantities of a few different types on the board, not the other way round.

Several things have changed, but will take a few more years to have a significant effect to reduce tantalum cap use.

Higher K ceramics are now really high K, 22uF in a matchhead, so can replace ali and tant in many places where you just need bulk C.
Newer LDO designs have got the stability problem sorted, so are stable with ceramics.
There is talk of niobium chemistry as a competitor to tantalum, but I've not heard too much about that recently, maybe the first two changes have reduced the urgency for its development.

I design minature test equipment, made in its 1000s to supply to manufacturers, not end user equipment made in 1000000s to supply to you and me, so in specifying tantalum caps, I've probably not killed too many children. Sony and I can also use the "Waldheim defense", "I voz only obeying market forces". Tantalum gets designed in because the economic attractiveness of its properties outweigh the human cost of its manufacture. They outweigh them because the human cost has no weight that features on the bottom line. I go to my boss and say "I can make the function >this< big, or I can make it > t h i s < big". No prizes for guessing which one we build. BTW, we use fossil fuel burning trucks to deliver our gear to customers (CO2 is only now starting to get a cost, but it's not appearing on the bottom line in any consistent way yet), but that's for a flame-war in the chatting forum!

GeordieBoy

Fri Jul 25 2008, 10:46AM

Registered Member #1232 Joined: Wed Jan 16 2008, 10:53PM
Location: Doon tha Toon!
Posts: 881

That explanation about the tants and LDO regulators is very interesting!

It is certainly true that the likes of Sony and also the Mobile Phone manufacturers do have a huge influence on others in the electronics industry. In a previous job I spent the best part of a month redesigning a company's product and testing it because one of the optocouplers used in the existing design had gone on allocation. It turns out that the entire world-stock of this opto-coupler (and forseeable future production!) had been bought up for some hand held gameboy in the run-up to Nintendo's Christmas demand! It must have cost the company I worked for thousands of pounds in engineers, draughtsman, purchasing people's time and a two days in a test-house for re-approval! So market forces definitely do have an influence on the smaller players.

-Richie,

aonomus

Fri Jul 25 2008, 08:53PM

Registered Member #1497 Joined: Thu May 22 2008, 05:24AM
Location: Toronto, Ontario, Canada
Posts: 801

This got posted to /. just a while ago

Interesting discussion there, people are on both sides of the fence quoting figures that 1% of the coltan market is from Africa, while others say that is just enough, etc, etc....

I just personally don't use tantalum caps unless I can avoid them, mainly cause of the non-graceful failure mode (read: bang).

The first comment, and most insightful is this:

Anything and everything fuels conflict in Africa. At most, this is throwing a match into a raging fire.

HV Enthusiast

Sat Jul 26 2008, 12:22AM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

We had a similar problem with tantalum capacitors about 8 years back. There was a major shortage in tantalums since the cell phone companies were buying them all up - it was a major problem for us.

rp181

Sat Jul 26 2008, 12:38AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
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Posts: 1529

is there even an advantage of having tantalum over other types? i dont see any.

Is it used in any other parts?

GeordieBoy

Sat Jul 26 2008, 01:03AM

Registered Member #1232 Joined: Wed Jan 16 2008, 10:53PM
Location: Doon tha Toon!
Posts: 881

As Dr Slack explained previously, Tantalum capacitors provide a desirable combination of compact size and almost ideal electrical characteristcs.

Well... almost ideal as long as you don't class failing with a bang and foul smell to be "non-ideal" behaviour! It's amazing how long that smell lingers after the failed cap has been replaced.

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