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Old 19th February 2012, 06:32 PM   #2361
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by the way, one of the LTSpice Group users mentioned this PDF -- illustrates how to derive models from datasheets: www.intusoft.com/lit/wkwModels.pdf
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Old 19th February 2012, 08:54 PM   #2362
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To #2348:
http://consist.sitesled.com/MATTES/Mattes.htm

US pat 3502996

AES E-Library A 200-Watt Solid State Stereo Amplifier
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The truth is out there. Who can handle the truth?
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Old 24th February 2012, 07:09 PM   #2363
godfrey is online now godfrey  South Africa
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Originally Posted by Bob Cordell View Post
Finally I have posted quite a bit of supplemental material for the book on my web site at CordellAudio.com - Home....
Hi Bob
A hearty thank you for those models and all the work that went into creating them. There's something I'm not sure about though.

You appended "C" to the end of the part numbers, presumably to distinguish them from other models for the same part that may be in the same library. However that doesn't really help when the part number ends with a "C" anyway, e.g. BC560C. I stepped around that by editing the text file and prefixing the part numbers with "bob", which gets them nicely grouped together in the alphabetical lists as well.

The remaining confusion is whether your models for e.g. BD139C and BC560C are actually models of the C grade components, or just the generic (ungraded) ones. Perhaps you could clarify?

Thanks - Godfrey
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Old 25th February 2012, 02:44 PM   #2364
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Originally Posted by godfrey View Post
Hi Bob
A hearty thank you for those models and all the work that went into creating them. There's something I'm not sure about though.

You appended "C" to the end of the part numbers, presumably to distinguish them from other models for the same part that may be in the same library. However that doesn't really help when the part number ends with a "C" anyway, e.g. BC560C. I stepped around that by editing the text file and prefixing the part numbers with "bob", which gets them nicely grouped together in the alphabetical lists as well.

The remaining confusion is whether your models for e.g. BD139C and BC560C are actually models of the C grade components, or just the generic (ungraded) ones. Perhaps you could clarify?

Thanks - Godfrey
Hi Godfrey, thanks for your kind words about the transistor models I built and posted on my web site. Yes, the C at the end of the models helped me distinguish between the models I created and those that came from manufacturers.

You are correct about the C possibly creating confusion with a C suffix on the real part numbers. At minimum, I should have adopted a convention where my C suffix was always an added suffix to a part number, so that a BD139 grade C would have been designated BD139CC.

The models I used for the BD139 were for the generic devices.

Cheers,
Bob
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Old 25th February 2012, 08:16 PM   #2365
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Originally Posted by Bob Cordell View Post
The models I used for the BD139 were for the generic devices.
Fairchild ones at least.

There is no way these can have a <50 MHz fT though, as some people have claimed. They are worse at lower Ic because capacitances are about twice as high as for the old Philips parts (so you'll want to run these at 10 vs. 5 mA, for example), but ultimately they should be in the same ballpark. They do have higher saturation current and a lot more beta droop.

Maybe the common STMicro parts use yet another die?

Otherwise I could imagine worse parts to use in a class A headphone buffer at 50..100 mA. (As, in fact, found in at least one commercial amplifier.)
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Old 25th February 2012, 08:54 PM   #2366
wahab is offline wahab  Algeria
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For BD139/140 Siemens old datasheet specify > 75 Mhz /f = 100Mhz/50mA/Vce = 10V ,
still short of Phillips s 160Mhz Typ/ f = 100Mhz/50ma/Vce = 5V.

Would be surprised if any other manufacturer claim such high Ft given
that neither STMicro nor Onsemi datasheets have Ft parameter.
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Old 25th February 2012, 09:10 PM   #2367
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Assuming the models are accurate, maximum fT shouldn't be too far off from the Philips parts (I used the formula given here to calculate it). tf is in the same ballpark for both.

So I'm a little puzzled as to why fT wouldn't be spec'd, at least for the Fairchild parts. It should still easily exceed 100 MHz at 50 mA. That's nothing to be ashamed off in an inexpensive medium power transistor.
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Old 25th February 2012, 09:37 PM   #2368
jcx is online now jcx  United States
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its unlikely any current production of a 30 yr old part is literally the same die, same process as original

http://www.onsemi.com/pub/docs/pcn/13135.pdf

presumably better die attach, metallurgy, molding, passivation allow the smaller die to handle the same power
but it seems likely junction C, ft have to change - hopefully for the better
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Old 29th February 2012, 12:51 PM   #2369
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Ions ago I got the information from philips that these bd parts are the same die as bc637,8.9 ect series but put into to126 case for higher dissapation. Looking at the datasheets this seems to be the case as youll notice they are virtually identical except for Max Ic and power ratings. Paracitic capacitances due to the package change will deteriorate performance a little. From what I can remember from my books there is a model parameter that can be used to sim this, I think it was Ccs but this was years ago since I was in the books so I could be wrong.
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Old 16th March 2012, 11:28 PM   #2370
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Hello Bob,
It's quite a while since I did anything on electronics... however I still need an OPS for my amp. I have proposition from Edmond but it seems difficult for me to understand so to make any progress I would like to use Edmond's OPS in a later design.
Now, I found an OPS that interests me a lot in your book on page 193 figure 10.7. It's the diamond buffer driver with flying baker clamps.
I use lateral mosfets for my OPS (SK1058/SJ162) is that OPS optimal for those type of output devices or is this circuit better for BJT's only?
On page 239 figure 11.16 is a mosfet output stage with folded drivers. Like the diamond driver is uses folded devices (drivers in this case - predrivers in the first case since it is based on a triple)
What would be the difference in both circuits if both used with my laterals?
Thanks a lot
Olivier
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