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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
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

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
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.

tiefbassuebertr 24th April 2016 06:11 PM

Who can upload the genuine datasheet from Siemens of this power BjT device (BD130 - ~2N3055):
1 x BD130 NPN Power Transistor 100V 15A 100W Siemens to 3 1pcs | eBay
All available versions online are not from Siemens.
Maybe there was no single pages - instead this the datasheet is content of a book like this:
SIEMENS, Halbleiter-Datenbuch 1970/71, STANDARD-Typen | eBay
thank you for upload.

JMFahey 24th April 2016 07:49 PM

1) maybe you are expecting the Siemens datasheet to show what you want to see ... there is no guarantee about that, might be the exact same as others you found.

2) old transistor datasheets showed a wide range of SOA conditions, with varying duty cycles or pulse widths, because the very same transistor could be used for almost *anything* , from a voltage or current controlled power supply (pure DC) to an audio amplifier to switching DC-DC converters at various frequencies, from 50/60Hz 12VDC (car battery) to 110/220V squarewave AC portable inverters to 400Hz (airplane duty) or 20kHz 12/24V DC (again car batteries) to, say, 60 to 500V DC power inverters.

In the late 60's, into the 70's I made all of them using 2N3055, go figure, because that was the industry workhorse, THE widely available powerful and inexpensive transistor, so datasheets had to cater to all those different users.

Today nobody would be crazy enough to use same transistor for those wildly different uses, we have a ton specialized ones to choose from.

3) I bet On Semiconductor envisions people using these for (analog) Audio use(read AB2 power amps) , in that case the 1 second SOA is all a Designer needs to know for an efficient short circuit protector, of any kind, from drive clamping to triggering a relay to shutting input signal off.

Why do you need detailed datasheets?
You want to repair/build an old circuit which used BD130?

I used tons of them myself , Philips made, rough beasts, slow but strong, I guess they were Hometaxials, definitely in the same league as RCA 2N3055H , way stronger than common epitaxial 2N3055E , so common that the E is dropped from the label .

MJ15015 or 2N3055A (if available) are good substitutes.
Trust me, I used all of them by the thousands for decades making Guitar/Bass amps, a very rough field use ... should I call it abuse?
By the way, if somebody found a couple thousand BD130 stash in an old warehouse, I'd buy them all (for a low price, of course) .

Struth 25th April 2016 02:20 AM

Hi Guys

I suspected that the 1-sec curve was meant to BE equivalent to DC.

These days with so many switching devices, there are mny where the DC condition is not given. However, you can extrapolate the DC and closer-to-DC curves since the times are always spaced by a decade and the graph is already logarithmic. For example, say the 10ms and 100ms curves are given. These might be spaced by, say, 1cm on a given size of the graph. You can then draw a curve 1cm below the 100ms one to have the 1sec curve.

For most BJTs designed for linear use, as all those MJ-pairs Jim mentioned were, you see the DC curve equally spaced below the 100ms curve compared to spacing for shorter time curves.

It is telling when you look at those super-power mosfets that are 1kW in a TO-264 package. The extrapolated DC curve puts their true dissipation at 150-250W. To run them at their rating requires liquid cooling to -10C or so.

For the MJL2119x use the 1s curve as DC and you'll be safe.

Have fun

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