EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: garvind25 on October 04, 2017, 08:27:26 am
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Hi,
Can anyone suggest any cheap and easily available substitutes for BC547A in smd package pls.
Thanks,
Arvind Gupta.
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Take a look at the BC847
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THIS (https://alltransistors.com/crsearch.php?mat=Si&struct=NPN&pc=0.5&ucb=50&uce=45&ueb=6&ic=0.1&tj=150&ft=200&cc=4.5&hfe=110&caps=TO92) could help.
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MMBT4401 and a million others. It's a general purpose BJT.
Tim
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The BC547 series is readily and inexpensively available in SOT-23 surface mount packages from Nexperia and others.
Applications relying on the 45 Vceo 50 Vcbo voltage rating of the BC547 would require something better than the ubiquitous 2N3904 or 2N4401.
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There are also tiny little dual NPN, NPN/PNP and dual PNP packages available in 6-pins (SOT?363/SC?88) of the BC846/7
Really great, saves a lot of space when needed :)
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OK... are you aware of any quad packaged bjts (4 npn txs. in one) in smd packing. Characteristics similar to BC547A and hopefully easily available :P
Regards,
Arvind Gupta
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For the BC5xx series there are equivalent BC8xx for the SMT versions. So it's relatively easy to find. For many of the 2Nxxxx there are MMBFxxxx SMT equivalents. However one might have to check for possibly different thermal properties.
There are not many transistor arrays any more. So the rather cheap dual BC847 s are already a positive exception. They are two dies in one case, though: so unlike older arrays not so well coupled and matched, but better isolated.
For use as a current mirror, there are also BCV62, two transistors already partially connected.
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OK... are you aware of any quad packaged bjts (4 npn txs. in one) in smd packing. Characteristics similar to BC547A and hopefully easily available :P
Regards,
Arvind Gupta
www.digikey.com (http://www.digikey.com) (or otherwise google)
Here a shortcut:
https://www.digikey.com/products/en/discrete-semiconductor-products/transistors-bipolar-bjt-arrays/277?FV=ffe00115%2C1280055%2C1f140000&mnonly=0&ColumnSort=1000011&page=1&stock=0&pbfree=0&rohs=0&cad=0&datasheet=0&nstock=0&photo=0&nonrohs=0&newproducts=0&quantity=&ptm=0&fid=0&pageSize=25 (https://www.digikey.com/products/en/discrete-semiconductor-products/transistors-bipolar-bjt-arrays/277?FV=ffe00115%2C1280055%2C1f140000&mnonly=0&ColumnSort=1000011&page=1&stock=0&pbfree=0&rohs=0&cad=0&datasheet=0&nstock=0&photo=0&nonrohs=0&newproducts=0&quantity=&ptm=0&fid=0&pageSize=25)
I don't see any benefits with a ques package. They are bigger than two dual packages and more expensive.
So you would need a very specific purpose for it.
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Quad arrays all suck, and you waste more space routing them anyway. :-\
I've used BC857BS (SOT-363) before. Layout is still a bit annoying for most use cases, but I think it's still a net win over SOT-323 (and surely is on cost).
Tim