PSpice Models for 2955/3055

mirlo

Member
Paid Member
2002-07-12 9:55 am
San Diego
I think this is going to be tough, at least to get one whose results can be trusted, because these devices are so old and so many manufacturers make parts with these labels. I don' t think that parameters are very well controlled for them, so if you get a spice model for a device made on a fast process that happens to be labelled 3055 it may not be at all representative of reality for an older or slower process.

I think Bob Pease had something to say about the wide variation in old numbered power transistors, how a circuit that always worked perfectly with the slow ones from mfr X would always oscillate with a fast one from mfr Y or vice versa, even though the devices had the same @Nxxxx number.

You MIGHT be able to get away with using models for MJ802 and MJ4502 if you can find those. (Sorry, I don't have 'em)
 
Pspice models

Here's one:

*2N3055
*Si 115W 70V 15A 20kHz pkg:TO-3 3,2,1
.MODEL 2N3055 NPN(IS=4.66E-12 BF=360 VAF=100 IKF=0.25 ISE=3.339E-11
+ BR=2 ISC=5E-9 RB=3 IRB=0.001 RBM=0.4 RC=0.04 CJE=5.802E-10 VJE=1.2
+ MJE=0.45 TF=8E-8 XTF=1 ITF=3 PTF=120 CJC=2.121E-10 MJC=0.4 TR=2.55E-6
+ XTB=1 )

Looking for the other one...

Jan Didden
 
And here's the other, MJE2955

*.model MJE2955 ako:NSC_5A PNP() ; case Mot 90 (s)
.MODEL MJE2955 PNP(Is=66.19f Xti=3 Eg=1.11 Vaf=100 Bf=137.6 Ise=862.2f
+ Ne=1.481 Ikf=1.642 Nk=.5695 Xtb=2 Br=5.88 Isc=273.5f Nc=1.24
+ Ikr=3.555 Rc=79.39m Cjc=870.4p Mjc=.6481 Vjc=.75 Fc=.5
+ Cje=390.1p Mje=.4343 Vje=.75 Tr=235.4n Tf=23.21n Itf=71.33
+ Xtf=5.982 Vtf=10 Rb=.1)

Or as TIP2955, in a TO220 case:

*.model TIP2955 ako:NSC_5A PNP() ; case TO-220 (s)
.MODEL TIP2955 PNP(Is=66.19f Xti=3 Eg=1.11 Vaf=100 Bf=137.6 Ise=862.2f
+ Ne=1.481 Ikf=1.642 Nk=.5695 Xtb=2 Br=5.88 Isc=273.5f Nc=1.24
+ Ikr=3.555 Rc=79.39m Cjc=870.4p Mjc=.6481 Vjc=.75 Fc=.5
+ Cje=390.1p Mje=.4343 Vje=.75 Tr=235.4n Tf=23.21n Itf=71.33
+ Xtf=5.982 Vtf=10 Rb=.1)

This is the best I can do for now.
 
That's a good idea, Jan.

*.model MJE3055 ako:NSC_4A NPN() ; case Mot 90 (s)
.MODEL MJE3055 NPN(Is=457.5f Xti=3 Eg=1.11 Vaf=50 Bf=156.7 Ise=1.346p Ne=1.34
+ Ikf=3.296 Nk=.5961 Xtb=2.2 Br=7.639 Isc=604.1f Nc=2.168
+ Ikr=8.131m Rc=91.29m Cjc=278.7p Mjc=.385 Vjc=.75 Fc=.5 Cje=433p
+ Mje=.5 Vje=.75 Tr=1.412u Tf=37.34n Itf=35.68 Xtf=1.163 Vtf=10
+ Rb=.1)

------------------------------

*.model TIP3055 ako:NSC_4A NPN() ; case TO-220 (s)
.MODEL TIP3055 NPN(Is=457.5f Xti=3 Eg=1.11 Vaf=50 Bf=156.7 Ise=1.346p Ne=1.34
+ Ikf=3.296 Nk=.5961 Xtb=2.2 Br=7.639 Isc=604.1f Nc=2.168
+ Ikr=8.131m Rc=91.29m Cjc=278.7p Mjc=.385 Vjc=.75 Fc=.5 Cje=433p
+ Mje=.5 Vje=.75 Tr=1.412u Tf=37.34n Itf=35.68 Xtf=1.163 Vtf=10
+ Rb=.1)
 

mirlo

Member
Paid Member
2002-07-12 9:55 am
San Diego
dumb question

The MJE & TIP models appear identical, so they don't account for possibly different package parasitics.

But that's not the question. Actually two questions.

Are MJE/TIP3055 and MJE/TIP2955 supposed to be replacements for the TO-3 case 2N3055 / MJ2955 ?

I don't think you can trust that Moto's numbering is meaningful here. For example, I think MJE802 is a darlington while MJ802 is (was?) a single big NPN.

Also, note that the parameters wrt beta (BF, BR) and Ft (TF) are WAY different for the 2N3055 model and the MJE3055 model ...

caveat simulator (good advice in all circumstances)
 
I know this thread has been dead for more than 10 years, but I couldn't find decent models that work properly together.

There has been so many variants of the 3055 and the other flavors of the 2955, it's hard to find models that match for both the npn and pnp.

I would like to find recent models for the fast types manufactured now. I suppose from ST or perhaps OnSemi.

Using LTSpice, there is no 2955 in its parts database and I suspect the 2N3055 that comes in its database must be rather recent, but we don't know where it came from and what parts it corresponds to. That model works well and I have used it on quasi complementary amps with no problems.

However I was trying to find an MJ2955 that could match it, and it seems nothing I have found so far is correct.

The models available on onsemi's site are rather old (2004), but they may be recent enough if nothing has changed further since. They have 3 different models for the 3055 in sp3 format, one of them not correct, because it's for a darlington, a different beast, and they call it a 2N3055A.

I have tried with their MJ2955 model and the one for the 2N3055H, but this doesn't seem well matched.
 

wg_ski

Member
2007-10-10 5:21 pm
Use MJ15015 and MJ15016 models. They should have the same poor hFE characteristic as the 3055 at high current. AFAIK, breakdown (and definitely s/b) is not modeled anyway. DO NOT use MJ802/4502 models - they are well matched and the hFE will be WAY optimistic.
 

wg_ski

Member
2007-10-10 5:21 pm
I use simulators as a guideline - I never take the results as gospel. There are too many other things about the circuit, the layout, and the components that are NOT modeled and have a huge impact on whether you can get to .00x% distortion or not. A decent model will help get out major problems, assess stabillity, compare topologies, etc.

The NPN and PNP from most "complementary pairs" of power transistors aren't very well matched. Not even the modern ones. The MJ802/4502 tend to be better matched than most but that was really dumb luck not something they did specifically when they were designed. But they are also a 25A part that has typical hFE of 20-ish at 25A, and totally not like the 3055 which has a typical hFE of 7 at 10A. Which is why you want 3 in parallel, use an 8A driver, and a triple in the first place. People always bash 3055's about poor SOA and that's not really the problem. The load on the driver typically is. An MJE1503x's are CHEAP so I don't see what the big deal is.

An EF3 would be possible using the 3055/2955 complementary. Even with a poorer match it will lilkely give a better result than the all NPN, just because it will give you less stability problems that you have to overcompensate for. The only real isssue is bias tracking but there are ways of fixing that too.
 
I use simulators as a guideline - I never take the results as gospel. There are too many other things about the circuit, the layout, and the components that are NOT modeled and have a huge impact on whether you can get to .00x% distortion or not. A decent model will help get out major problems, assess stabillity, compare topologies, etc.

Agreed! And in this case, it was mostly curiosity that made me look for the 2955 model so I could compare the topo in complementary to the quasi.

With the models of the 2955 that I found, it doesn't work right and oscillate a lot. I couldn't stabilize it properly and I don't want to put too high values caps all over the place to put a damper on it.

The NPN and PNP from most "complementary pairs" of power transistors aren't very well matched. Not even the modern ones.

And the MJ15015/6 have a big difference right on the datasheet, their Ft. I think this could be a good possible cause for oscillations.

I don't see any noticeable oscillations in the quasi 3055 amp, and I even get 0.000xx% thd on 8ohms at 1khz, so this can work well and if there were any oscillations, the thd would shoot way up fast.

The thing is, keeping the 3055 models that come with ltspice and then use the mj2955 from onsemi, the oscillations are too difficult to get rid of. What I see is all on the lower part of the sine wave, on the 2955 side.

parallel, use an 8A driver, and a triple in the first place. People always bash 3055's about poor SOA and that's not really the problem. The load on the driver typically is. An MJE1503x's are CHEAP so I don't see what the big deal is.

Neither do I, and we're getting fair results with them.

An EF3 would be possible using the 3055/2955 complementary. Even with a poorer match it will lilkely give a better result than the all NPN, just because it will give you less stability problems that you have to overcompensate for. The only real isssue is bias tracking but there are ways of fixing that too.

I'm not sure yet about tracking, but my attempts at stabilizing the 3055/2955 config hasn't yet been successful.

I did try it with the MJ15015/6, and most, but not quite all, of the oscillations are gone, and it does work better, however there are still small signs of oscillations and I haven't yet been able to get rid of that and the thd hasn't come down as much as on the quasi.

I'm posting the models of the MJ15015/6 with this message, for others to use. It's the sp3 format, from onsemi.
 

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wg_ski

Member
2007-10-10 5:21 pm
My experience is that stabilizing the complementary has been easier, not harder. Not in simulation land, but on real hardware. The worst was a quasi-2N3773 that used a triple and 6 in parallel. Worked "ok" with a normal power supply - just a bit temperamental but eventually stable. Hooked up the class H rail switches and EVERY time the negaive rail switched in, it broke into uncontrollable destructive oscillations. Tried every imaginable compensation scheme - and no dice. In a fit I finally replaced the negative bank with a bunch of MJ15016's, turned it on, and it's been working flawlessly ever since.

Not too long ago, I put together a little test circuit running 3 pair of 3055's in quasi triple, running off a 20-0-20 trafo. Got 120W in 2 ohms with useable SQ. Then built a complementary version right next to it. The quasi and the comp EF3 worked equally well with no oscillation problems, but the quasi needed a bit more bias to get rid of the crossover distortion.
 
2N3773 that used a triple and 6 in parallel. Worked "ok" with a normal power supply - just a bit temperamental but eventually stable. Hooked up the class H rail switches and EVERY time the negaive rail switched in, it broke into uncontrollable destructive oscillations. Tried every imaginable compensation scheme - and no dice.

I have a big bunch of left over older 3773s in stock. I was thinking about doing something with them some day, but they might turn out to be a hand full. I have some old bgw amps schematics. That's what they used for a long time and they made beefy amps with them, and robust too.

How many trannies did you blow?

In a fit I finally replaced the negative bank with a bunch of MJ15016's, turned it on, and it's been working flawlessly ever since.

You mean you kept half of the 3773s and used them with the MJs? Are they that close to be used together?

Not too long ago, I put together a little test circuit running 3 pair of 3055's in quasi triple, running off a 20-0-20 trafo. Got 120W in 2 ohms with useable SQ. Then built a complementary version right next to it. The quasi and the comp EF3 worked equally well with no oscillation problems, but the quasi needed a bit more bias to get rid of the crossover distortion.

I am right now re-configuring the test that I was doing with the MJ15015/6, so the output triple is now a standard EF triple, with that floating resistor on the pre-drivers and the drivers. I'm doing this on the highly modified amp that we're working on to be used as a grounded bridge. I'm exploring possibilities and looking for cheap improvements that can be made so we get a much better amp for not so much more money.

So far, with an approach like that of Bob Cordell's, I incrementally added improvements and did some tweaking on values and various little things. What I was able to do so far is very encouraging, because the overall distortion levels have dropped a whole lot (check back that thread). And I did all this without doing any exact calculations on many parts, so I'm sure with proper calculations done, what I did can be improved further.
 

wg_ski

Member
2007-10-10 5:21 pm
How many trannies did you blow??

Maybe two dozen. Along with a bunch of IRF1407's and their drivers. The positive side usually held up, but the lower set would occasionally die - even with the lightbulb limiter!

You mean you kept half of the 3773s and used them with the MJs? Are they that close to be used together?.

I replaced the lower half with the MJ's because they were the spare PNP's that I had on hand. I went from a quasi to a "complementary" EF3. Even though they aren't even close to being complementay it still worked well. With that much gain and current capacity it doesn't really matter what you put in there. I'm sure the heavily-resistively-loaded VAS had something to do with it too. The front end was 2 gain stages + VAS, kind of like OSTripper's GLA - which also used an EF3 output. I still never got a good explanation why the quasi output stage was unstable with varying rails. Hopefully the grounded bridge will be ok with it - the rails will be slowly varying instead of hard switched.
 
The ON Semi models may not be typical. I don't know if they have updated their models but a while back the models were aimed at worst case. The Early voltage may be low (Vaf=100) and this may cause more distortion than warranted. Some 3055's with high breakdown voltage may have Vaf's of 200.

The tf of the 3055 should be around 50nS while the MJ2955 might be 25nS. This may cause some mismatch between output halves in a 3055/2955 amp - just increase the sprog stopper on the PNP stage a little!

John