TIP162 (Darlington NPN) Substitute?

Discussion in 'General Electronics Chat' started by TheLaw, May 14, 2011.

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  1. TheLaw

    Thread Starter Member

    Sep 2, 2010
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    Hey everyone,

    So if you were wondering, I scratched the solar cell project that I made a thread about before, if you remember...I found something a bit more interesting.

    My dad loves his car and since he's retired he can spend a lot more time with it than when he was working. I saw this Velleman K2543 kit which is a electronic ignition amplifier, similar to the ignition boxes you see in high performance muscle cars.

    I don't have too much faith in the junk Velleman bundles in their kits, and I'm less comfortable with them running the ignition system on a car...so I'm going to etch the PCB myself and source the components myself also.

    There's one problem. I was able to find every component except for a Darlignton transistor called the TIP162, which was originally manufactured in the 70s by Bourns. They are no longer made, and any replica you buy of it is from either NTE or some no-name brand. I'm not comfortable with using those either. (I can't imagine Velleman is packaging a genuine Bourns chip either.)

    So, my question is: Can I choose a different Darlington NPN transistor with specifications exceeding those of the TIP162 and drop it in?

    I found this ST Darlington that has Max operating specs that are much better than the TIP162: http://www.mouser.com/ProductDetail...=sGAEpiMZZMupZfs/wBb3DGpkiAxa96AGlAaesqTuzAc=

    Can I simply use this one instead? I don't know how Darlingtons work, so I'd be curious if I could just use that BU941 from Mouser. Is it possible?

    Thanks.

    EDIT: I hope this doesn't fall under automotive modifications. I swear I won't sue any of you guys. :p
     
    Last edited: May 14, 2011
  2. Wendy

    Moderator

    Mar 24, 2008
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    Do you know what a TO-3 case style is? That part has it.

    Usually using a part with better specifications is not a mistake.
     
  3. TheLaw

    Thread Starter Member

    Sep 2, 2010
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    Yes I know that is a TO-3 package. I think that is partly why it has pretty good specs...

    Thanks.

    But in regards to Darlingtons, are they "exchangeable" like this? I know in some transistor applications, (mainly audio), that you can't necessarily just use different transistors because it would have adverse effects. Is this not so for this type of application? I can get a TO-220 style package with specs that are not quite as good, but for automotive, I think it would better to use really resilient components that can take a beating.
     
  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    That looks like it should work.
    The Bourns datasheet shows added zener protection in the test circuit. ST also makes BU941ZP, which has an integral zener.
     
  5. Wendy

    Moderator

    Mar 24, 2008
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    The main thing about the TO-3 is it is not a stand alone case style, a heat sink is planned as part of the package. With a TO-220 it is more of an option.

    As for substitutions in general, you take your chances. I have heard the term "audition" used when it comes to trying out a new part for an established design. If the specs are better overall then you are probably OK, but Murphy can always step in when least wanted or expected.
     
  6. TheLaw

    Thread Starter Member

    Sep 2, 2010
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    What do you mean by integral zener? I see a zener on both the BU941 and the BU941ZP, no?

    Are you suggesting that ZP because it is a different package? (ZP almost seems like it would be Zener-Protection), but it seems that both have Zeners.

    How would the Velleman circuit be affected? Or would it remain the same?

    Schematic is attached.
     
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  7. TheLaw

    Thread Starter Member

    Sep 2, 2010
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    Right, I understand. I was curious if there were any really big differences between the Darlington-type transistors.

    The Darlington NEEDS to be heatsinked or it will overheat badly, especially with it being in the engine bay of a car. So I'm hoping to bolt it onto a fat aluminum heatsink and then run wires from the PCB to the TO-3.

    Thanks.
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The TIP162 is a TO-247 package; like a large TO-220.

    Running wires from the board to the TO-3 package will likely cause problems due to the inductance of the wiring.

    Since this is an automotive topic, I don't think we can discuss it anymore due to the new Terms of Service, which prohibit discussion of any automotive-related discussions. There are links to some other websites where you can discuss the circuit in this thread:
    http://forum.allaboutcircuits.com/showthread.php?t=54400
     
  9. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    I don't see an integral zener in the BU941 datasheet. The BU941ZP has one.
    See the attachment.
    The Velleman circuit has external zeners, so an integral zener would eliminate the need for those.
     
  10. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Due to safety and / or enviromental issues I am closing this thread.

    Quote:
    6. Restricted topics. The following topics are regularly raised however are considered “off-topic” at all times and will results in Your thread being closed without question:

    • Any kind of over-unity devices and systems
    • Automotive modifications
    • Devices designed to electrocute or shock another person
    • LEDs to mains
    • Phone jammers
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    • Transformer-less power supplies
    This comes from our Tos:
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    There will be enough sites where the subject can be discussed : Member selected automotive forums

    Bertus
     
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