SMT Equivalent of 2N3904 Transistor?

Log in or register to post comments
Go To Last Post
12 posts / 0 new
Author
Message
damien_d
damien_d's picture
Level: Resident
Joined: Mon. Dec 15, 2008
Posts: 923 View posts
Location: Brisbane, Australia
#1
Posted by damien_d: Sat. Dec 29, 2012 - 03:09 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Dear all,

I'm looking for a SMT NPN transistor about the equivalent of the 2N3904, say in a SOT-23 package or similar? Normally I'm a software guy, but I am trying to create a really cheap design for my Dad's model train club :)

The original in a TO-92 package looks to go for under 10c in 1K volumes, which would be rather nice :)

Ideas?

Tags:

Learning and Information, General Electronics
Top
damien_d
damien_d's picture
Level: Resident
Joined: Mon. Dec 15, 2008
Posts: 923 View posts
Location: Brisbane, Australia
Posted by damien_d: Sat. Dec 29, 2012 - 03:12 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Oops... I feel like a dill... the MMBT3904 is the ticket, but I'm still open to suggestions :)

Top
jgmdesign
jgmdesign's picture
Level: Moderator
Joined: Mon. Mar 19, 2007
Posts: 17041 View posts
Location: Long Island New York
Posted by jgmdesign: Sat. Dec 29, 2012 - 05:15 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

2N2222A, 2N4124?

Google "General purpose NPN transistor" and see what happens.

I entered "NPN transistor" in one of digikeys searches and got 16,000+ possibilities :shock:

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

Top
damien_d
damien_d's picture
Level: Resident
Joined: Mon. Dec 15, 2008
Posts: 923 View posts
Location: Brisbane, Australia
Posted by damien_d: Sat. Dec 29, 2012 - 05:35 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

jgmdesign wrote:
I entered "NPN transistor" in one of digikeys searches and got 16,000+ possibilities :shock:

... which is precisely the problem :)

Top
mckeemj
mckeemj's picture
Level: Resident
Joined: Sun. Jun 25, 2006
Posts: 869 View posts
Location: San Luis Valley, Colorado ( 2,318m )
Posted by mckeemj: Sat. Dec 29, 2012 - 06:56 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I actually like Digikey's search ( as distributor parametric searches go ). Drill down through it by adding requirements and sort by most important factor. The MMBT2222ALT3G from ON Semiconductors looks nice. It's got a 600mA rating, minimum gain of 100, comes in SOT-23 and is $0.10/25. Time to find... thirty seconds ( Discrete Semiconductors->Transistors (BJT) - Single, search for In-Stock, NPN, hfe > 100, surface mount - sort price ascending ).

Martin Jay McKee

As with most things in engineering, the answer is an unabashed, "It depends."

Top
damien_d
damien_d's picture
Level: Resident
Joined: Mon. Dec 15, 2008
Posts: 923 View posts
Location: Brisbane, Australia
Posted by damien_d: Sat. Dec 29, 2012 - 07:31 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Any other particularly common ones that "everyone" uses?

Top
Plons
Plons's picture
Level: Raving Lunatic
Joined: Tue. Nov 1, 2005
Posts: 7049 View posts
Location: Hilversum - the Netherlands
Posted by Plons: Sat. Dec 29, 2012 - 12:42 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

BC547/548/549. In smd these are called BC847 etc. Their max Ic=100mA though.

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tessa and Tina, You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

Top
damien_d
damien_d's picture
Level: Resident
Joined: Mon. Dec 15, 2008
Posts: 923 View posts
Location: Brisbane, Australia
Posted by damien_d: Sat. Dec 29, 2012 - 10:46 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Plons wrote:
BC547/548/549. In smd these are called BC847 etc. Their max Ic=100mA though.

I was wondering what they were called in SMT :)

-- Damien

Top
Plons
Plons's picture
Level: Raving Lunatic
Joined: Tue. Nov 1, 2005
Posts: 7049 View posts
Location: Hilversum - the Netherlands
Posted by Plons: Sat. Dec 29, 2012 - 11:03 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Lovely huh ? Just add 300 to the partnumber.

BC847 in package SOT23 for the single ones, but there are also duals: BC847BPN in SC-88 (or SOT363)

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tessa and Tina, You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

Top
alexan_e
alexan_e's picture
Level: Resident
Joined: Thu. Jul 5, 2007
Posts: 994 View posts
Location: Greece
Posted by alexan_e: Sat. Dec 29, 2012 - 11:25 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I like these two (NPN/PNP), rated to 30v/700mA with high gain

http://www.unisonic.com.tw/datas...
http://www.unisonic.com.tw/datas...

Alex

"For every effect there is a root cause. Find and address the root cause rather than try to fix the effect, as there is no end to the latter."
Author Unknown

Top
damien_d
damien_d's picture
Level: Resident
Joined: Mon. Dec 15, 2008
Posts: 923 View posts
Location: Brisbane, Australia
Posted by damien_d: Sat. Dec 29, 2012 - 11:45 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

alexan_e wrote:
I like these two (NPN/PNP), rated to 30v/700mA with high gain

Fortunately, the design (bi-colour LED driver, with latch) is rather tolerant of low (and variable) gain :)

-- Damien

Top
alexan_e
alexan_e's picture
Level: Resident
Joined: Thu. Jul 5, 2007
Posts: 994 View posts
Location: Greece
Posted by alexan_e: Sun. Dec 30, 2012 - 12:20 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Basically you can use a higher base resistor and limit the current that the AVR pin has to provide.
This can be useful in some cases or maybe to reduce the consumption.

I find these transistor especially useful for some ARM mcu that can provide only 3mA per pin.

Alex

"For every effect there is a root cause. Find and address the root cause rather than try to fix the effect, as there is no end to the latter."
Author Unknown

Top