SMD substitute for BC547A - Page 1
Forum section: electronics / projects

author: garvind25
author_rank: Regular Contributor
timestamp: October 04, 2017, 08:27:26 am
content: Hi,Can anyone suggest any cheap and easily available substitutes for BC547A in smd package pls.Thanks,Arvind Gupta.

author: Qw3rtzuiop
author_rank: Frequent Contributor
timestamp: October 04, 2017, 08:30:47 am
content: Take a look at the BC847

author: ElektroQuark
author_rank: Unknown
timestamp: October 04, 2017, 08:37:24 am
content: THIScould help.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 04, 2017, 09:32:56 am
content: MMBT4401 and a million others. It's a general purpose BJT.Tim

author: David Hess
author_rank: Super Contributor
timestamp: October 05, 2017, 01:32:35 am
content: 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.

author: b_force
author_rank: Super Contributor
timestamp: October 05, 2017, 01:35:53 am
content: There are also tiny little dual NPN, NPN/PNP and dual PNP packages available in 6-pins (SOT?363/SC?88) of the BC846/7Really great, saves a lot of space when needed

author: garvind25
author_rank: Regular Contributor
timestamp: October 05, 2017, 03:08:59 pm
content: OK... are you aware of any quad packaged bjts (4 npn txs. in one) in smd packing. Characteristics similar to BC547A and hopefully easily availableRegards,Arvind Gupta

author: Kleinstein
author_rank: Super Contributor
timestamp: October 05, 2017, 04:34:40 pm
content: 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.

author: b_force
author_rank: Super Contributor
timestamp: October 05, 2017, 04:56:30 pm
content: Quote from: garvind25 on October 05, 2017, 03:08:59 pmwww.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=25I 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.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 05, 2017, 05:11:25 pm
content: 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