BD139/140 driver

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#3
MJE340/350 are ancient old favourites.
 

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#7
BD139/140 from fairchild, onsemi or stmicro should work quite well.
Just look for 10 or 16 versions, otherwise, they can have fairly low
current gain if the batch is mediocre..
Models from nxp/phillips are preferable, though...

Edit: in my spice library, the fairchild are faster than the phillips.
The onsemi are the worse.
Worth adding that generaly, fairchild has correct spice models.
 
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#8
Rafael L said:
Hello to All

I'm designing an amplifier and would use the BD139/140 as drivers (good in simulation "Fairchild").
Told me that the good BDs are only the old Philips.
Datasheet BD139 Philips-1999 and BD139 ST-recent:
BD139-16 Datasheet pdf - Transistor de poder de NPN - Philips

I saw very recent projects to BD139/140-16, which is the FT(190Mhz???), these newer BDs?
Click to expand...

The company I work for assembles an instrument used for electrochemical impedance spectroscopy. It's basically a simple device but one that demands high quality components be used to meet incredibly stringent linearity and noise specs. E.g. 5-10% of the AD797 exhibit the "popcorn effect" and need to be replaced for the device to be within noise specs.

One of the components in it has some BD139/140, we are specifically NOT allowed to use Philips. ON is specified instead, and these have never given any problems. You might consider these yourself.
 
#9
For Driver applictions in audio amplifiers Cob and popcorn noise are not paramters I would concern myself with. For a VAS transistor, it is of course a completely different story -there Cob is critical, although I would assume popcorn noise less so (popcorn noise on a device designed to conduct 10's of mA sounds a bit strange to my ears I have to admit).

Therefore, provided your design does not exceed the Vce breakdown spec, I don't see a problem with the BD139/140 from any supplier.
 
#10
I mentioned the popcorn effect mostly as an illustration of the tight specs this device is subject to. We're talking 4 nA pp noise into a 1k load, not something you'd worry about in an audio device. The name was derived from the fact that it sounds like corn popping when played through speakers, though...

I don't know the reason for the exclusion of the Philips BD139/140 in this product, but I mentioned it because OP implies that these would be the only good ones.
 
#11
We're also making an AD797 intensive device and having problems with excessive popcorn noise on these opamps.

Any suggestions on a test circuit to excite the problem? I think we're going to need to do batch testing before stuffing our boards.
 
#15
I am also using BD139/40-16(ST) as drivers in one of my amp driving 2 pairs of 2sc5200/a1943, supply is +/-42V DC.
I have tried other transistors also in the drivers keeping the BD139 in VAS.
2sc4793/a1837: average bass, good mids, good highs
MJE15032/15033: excellent bass, good mids, good highs
BD139/140: very good bass, excellent mids, excellent highs.

I found the BD's most pleasant sounding, in my amp particularly.

Cheers!!

Aniket
 
#18
Some old but obsolete and faked favourites like Renesas 2SD669/B649 and Toshiba 2SC4793/A1837 are now produced by Unisonic (Taiwan) and available economically through Profusion PLC. (UK, Germany). Possibly there are other global distributors who are not just selling fakes.
I've bought and used the original Renesas types and these are certainly as good as drivers, though I haven't used them yet in the VAS transistor role.
There's a few types worth consideration in this list: Medium Power-Driver
 
#20
For VAS duty 2sc3902, 2sc4027, 2sc3648 and complementaries available from Onsemi, are also good devices if you can't source ksc3503/1381. these can also be used as drivers in medium power amps.

2sc3902 is in TO126 package and has good specs.

Regards,
Aniket
 
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