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-   -   MJ21193/MJ21194 (MJ 21193 21194) - no data for SOA during dc conditios (http://www.diyaudio.com/forums/solid-state/150020-mj21193-mj21194-mj-21193-21194-no-data-soa-during-dc-conditios.html)

tiefbassuebertr 27th August 2009 10:13 AM

MJ21193/MJ21194 (MJ 21193 21194) - no data for SOA during dc conditios
 
There is only the condition for 1 sec, but not for DC in the SOA diagram (please refer fig. 13, page 4) about
http://www.onsemi.com/pub_link/Collateral/MJ21193-D.PDF
In the SOA-diagram of the datasheet MJ15015/15016/2N3055A
there are different conditions (for 30us,100us, 1ms and 100ms) so as DC condition (please refer fig. 12 and fig. 13, page 5
http://www.onsemi.com/pub_link/Collateral/2N3055A-D.PDF

Are there certainly calculation steps to determine self the dc conditions for MJ21193/MJ21194 SOA?
Thank you very much for your advices

wg_ski 27th August 2009 02:39 PM

The DC curve can always be generated for any device. In this case 250W at T=25C derating to zero at 200C. They usually put the 25C DC curve on the SOA graph for reference (MJ15015, etc.) but they don't have to because they've already supplied that information.

tiefbassuebertr 2nd September 2009 05:20 PM

1 Attachment(s)
Here I have both SOA Diagrams MJ21193 and MJ15025 from
http://www.onsemi.com/PowerSolutions....do?id=MJ15025
for directly compare, but I understand only this one from MJ15025

AndrewT 4th September 2009 11:57 AM

Hi T,

For Tc=25degC,
I see a current limit that matches the specification.
I see a power limit that matches the specification.
I see a plot of second breakdown that is not described in the specification.
Those SOA graphs seem to give all the information I need without any ambiguity.

What is the problem?

tiefbassuebertr 4th September 2009 12:36 PM

The problem is, that I have only the SOA for 1 sec and I want to understand, how I can generrated other times and dc conditions for directly compare to the other mentioned power devices.
Additional it would be of interest for me, why the SOA for MJ21194 is only for one second and this one for the older MJ types a wide range of different times for SOA (open the weblink in the beginning of this thread)

Additionaly I don't understand the follow:
=======================================
"The DC curve can always be generated for any device. In this case 250W at T=25C derating to zero at 200C. They usually put the 25C DC curve on the SOA graph for reference (MJ15015, etc.) but they don't have to because they've already supplied that information."
=======================================

what means this exactly concerning the comparable of SOA with different conditions for each types?

AndrewT 4th September 2009 01:01 PM

you cannot infer the shorter single shot durations from the DC or 1second ratings.
You cannot infer the second breakdown curve from the DC ratings.

You can easily find the low voltage and current ratings from the DC specification.

A 250W 17A device can pass <17A at <14.7V when Tc=25degC.
At >=14.7V the device can pass [250/Vce] amperes continuously when Vce is <= DC second breakdown limit.


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