TO-126 transistor equivalent

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EchoWars

EchoWars

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Joined 2003
#1
I need something in a TO-126-type package to replace a rather tough to find transistor (a 2SC1628). Needs to be rated for about 150V, 50-100mA, 1W, and 70MHz ft. Easy to find this with a BCE layout, but the tough part is that I need a CBE layout (or EBC).

Any ideas? Perhaps a 'BC-type' numbered part?
 
#2
MJE340 OnSemi Motorola

.
hi

😎 MJE340 ( OnSemi Motorola )
is often used instead of BD139, and such TO126,
when it comes to higher voltage than 80

From beginning MJE340 - MJE350 were intended for Video, TV applications
which can have rather high voltage and Fast Signals.
But as you know, it has been used ever so many times
in Hifi Power Amplifiers.
Both in professional commercial amps and in DIY.
----------------------

on the + : MJE340 can be found everywhere, to low price, pretty good for audio!
on the - : not much, but there are better, harder-to-find and more expensive transistors, today

For use 80 Volt and lower,
BD139 / BD140 will be clearly Better choice than MJE340 / MJE350
and should be used.


Regards 🙂 lineup
-----------------------
OnSemi datasheet and MJE340 Curves
http://www.onsemi.com/pub/Collateral/MJE340-D.PDF
 
#3
EchoWars said:
I need something in a TO-126-type package to replace a rather tough to find transistor (a 2SC1628). Needs to be rated for about 150V, 50-100mA, 1W, and 70MHz ft. Easy to find this with a BCE layout......
Click to expand...
1W in a T0126 package seems like overkill.
Do you need 1W of dissipation?
Do you need To126?

As far as I know all To126 are BCE and are the reverse of the ECB found in To220, To247 & To264.

BC To92 are usually EBC, but the L version is usually BCE like the To126.

To92 2N and Eline are usually CBE.
Zetex do a range of Eline that have 1W and 1.5W dissipation that can meet your spec. They are usually quite a bit more expensive than BC and other cheap To92. ZTX455 gets close, but only 140Vce0.

edit,
No, but he expects everyone else to read.
 
#8
MJE340 and BD139 are all ECB layout, unfortunately. And yes, I need the 1W rating. There's not a lot of current through them, but C-E voltage is rather high, and they're at close to 1/2W dissipation as it is...I want the 1W rating for a comfort zone.

BF758 is a good package (forgot about the old TO-202 package), but I cannot find a datasheet (or someone who sells them), and I need to see it. And I don't think I can bend the circular arrangement of the leads on the 2N5058 around to do the job.

Maybe a little Zetex with a 'flag' style heatsink...? I'd rather find a bit heavier-duty package.
 
#9
EchoWars said:
MJE340 and BD139 are all ECB layout, unfortunately.
.
Click to expand...

There are several ways around,
for different pinning attachment.

1. Carefully use a tool to bend legs, pins
into 'PCB wanted pinning' and so be able to fit into TO126 holes.

This is best done, while keeping MJE340 the legs LONG
and then afterwards, if possible/needed, cut them off.
Cut later from backside of PCB! .... goes for most all components!

2. Use short pieces of copper wires (short as possible ) as an adopter
for your transistors, to different PCB Pinnings.


Method 1. is to prefer.
As we strive to keep wires short, in audio amplifiers.
This is nothing new.
This most of us has had to do ... from time to time.



Regards 🙂 lineup
----------------------------------------------------------
A supply of MJE340 MJE350 is what a DIY builder could keep in 'his standard box'.
With the general purpose data of MJE340 MJE350
there is not much you can not do .. when need a Medium power BJT, such as TO126.
... 300 Volt and several watts at reasonably good gain and quality
... at low price & high availability, easy to find
... makes very good and useful Complementary Transistor devices
can we ask for more

Another very useful standard for you 'box':
2N5551 / 2N5401 ... 150 Volt small signals, very good audio transistors
... and these are not shy for a bit higher currents than BC550C / BC560C ( 45 Volt )
 
#10
There is no room to use a BCE component and bend the leads...board is too populated. Option #2 is too much of a hack...I'd save that as the ultimate last resort if all other options were exhausted, and even then I don't know if it could be done due to the limited space.
 
#11
Look at some of Fairchild's transistor range - they have plenty of parts in a "TO92L" package - a "stretched" TO92 capable of handling 1W.

They all seem to be ECB format... but you could very easily bend the legs (insulating them with "heatshrink" or so)
 
#14
Isn't there a small heat sink available for a TO-92L? There is for TO-18 metal cans. If not you could probably make an aluminum 'hat' easily. A small blob of HS grease, even with the epoxy case, Rthj-A should be better than just with air. Maybe improve the de-rating just enough for reliability at 1/2W. 🙂
 
#17
Here's a picture.
A longtime TO-92 heatsink manufactured overhere is a KK92, but only does 80C/W.
 

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