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From: dagmargoodboat on 13 Jul 2010 11:13
On Jul 13, 6:19 am, "Tim Williams" <tmoran...(a)charter.net> wrote:
> http://www.fairchildsemi.com/ds/FG%2FFGA30N120FTD.pdf
>
> Maximum collector current 60A at 25C.  I don't see any condition, taking a reasonable guess at Vce(sat) at max Tj, where this could possibly dissipate anywhere near the power rating of 339W (also at Tc = 25C).  In fact, the typical output characteristics show it should be closer to Vcesat = 3V, Ic = 120A, Vg = 15V.  So why pick 60A?
>
> More BS?  What's the real rating?  Buy from someone else?  Ha, no one else even has honest ratings...
>
> Tim
>
> --
> Deep Friar: a very philosophical monk.

Int'l RectiFryer: a very different kind of monk?

--
Cheers,
James Arthur
From: m II on 13 Jul 2010 11:29
dagmargoodboat(a)yahoo.com wrote:

>> Deep Friar: a very philosophical monk.
>
> Int'l RectiFryer: a very different kind of monk?



Specializes in the Sine of the Cross.






mike
From: dagmargoodboat on 13 Jul 2010 11:49
On Jul 13, 10:29 am, m II <c...(a)in.the.hat> wrote:
> dagmargoodb...(a)yahoo.com wrote:
> >> Deep Friar: a very philosophical monk.
>
> > Int'l RectiFryer: a very different kind of monk?
>
> Specializes in the Sine of the Cross.
>
> mike

Bless me Father, for I have sined.
From: Tim Wescott on 13 Jul 2010 11:51
On 07/13/2010 04:19 AM, Tim Williams wrote:
> http://www.fairchildsemi.com/ds/FG%2FFGA30N120FTD.pdf
>
> Maximum collector current 60A at 25C. I don't see any condition,
> taking a reasonable guess at Vce(sat) at max Tj, where this could
> possibly dissipate anywhere near the power rating of 339W
> (also at Tc = 25C). In fact, the typical output characteristics
> show it should be closer to Vcesat = 3V, Ic = 120A, Vg = 15V.
> So why pick 60A?
>
> More BS? What's the real rating? Buy from someone else?
> Ha, no one else even has honest ratings...

At a guess I'd say that they're concerned about uneven heating, so the
60A is what they think you can pull without the hottest spot exceeding
the junction temperature.

If true, IGB transistors have negative temperature coefficient, which
would concentrate current within the device as well as between devices
in the outside world.

But I've never even touched an IGBT, much less actually designed one
into a circuit. I'm just regurgitating old information...

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
From: Wimpie on 13 Jul 2010 12:08
On 13 jul, 13:19, "Tim Williams" <tmoran...(a)charter.net> wrote:
> http://www.fairchildsemi.com/ds/FG%2FFGA30N120FTD.pdf
>
> Maximum collector current 60A at 25C.  I don't see any condition, taking a reasonable guess at Vce(sat) at max Tj, where this could possibly dissipate anywhere near the power rating of 339W (also at Tc = 25C).  In fact, the typical output characteristics show it should be closer to Vcesat = 3V, Ic = 120A, Vg = 15V.  So why pick 60A?
>
> More BS?  What's the real rating?  Buy from someone else?  Ha, no one else even has honest ratings...
>
> Tim
>
> --
> Deep Friar: a very philosophical monk.
> Website:http://webpages.charter.net/dawill/tmoranwms

Hello Tim,

I think they didn't a bad job in their specification. Figure 5 is a
nice graph showing actual Vcesat versus case temperature and current
as parameter.

When you can get the case temperature below 60 degrees, it says Vcesat
= 2.5V at 60A. That is 150W resulting in a junction temperature of
about 117 degr. C. Assuming duty cycle < 100%, will result in less
stress. The difficulty may be in finding the switching loss for your
application.

Best regards,


Wim
PA3DJS
www.tetech.nl
without abc, PM will reach me.
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