Breadboarding region recommendations?

Discussion in 'General Electronics Chat' started by Roderick Young, Oct 25, 2015.

  1. Roderick Young

    Thread Starter Member

    Feb 22, 2015
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    Hi, I'm about to go to fab on a hobby PC board, but have a free area on it that is 0.77" x 0.585" . I would like to put some spare footprints in it, in case I want to fix something later. Any suggestions as to what I should put there? The entire board is about 9" x 9", consisting almost entirely of analog (dc-dc converter) circuitry. I was thinking I should at least put down some 1206 surface mount pads. Anything else?
     
  2. OBW0549

    Well-Known Member

    Mar 2, 2015
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    Maybe a SOT-23 or two? I suppose it all depends on what is it that you're most likely to want to "fix" in the future, and what sorts of components that might require.
     
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  3. dl324

    Distinguished Member

    Mar 30, 2015
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    I'd try to fit in something that would accommodate a range of parts; a derivative of these for instance:
    207378 (1).jpg 207360.jpg
    BTW, if anyone is looking to make their own SMT to SIP adapters, I have a number of the lead frames (pins) for barter or sale.
     
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  4. BReeves

    Member

    Nov 24, 2012
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    You can do what I did with a board that I was pretty sure would need further development work. I placed a bunch of pads with 0.1 inch spacing like a proto board in the free space I had left over.

    Image1.jpg
     
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  5. Roderick Young

    Thread Starter Member

    Feb 22, 2015
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    Per your recommendation, I've put in an SOT-23 footprint. Thanks!
     
  6. Roderick Young

    Thread Starter Member

    Feb 22, 2015
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    Good idea, I'm going to do that, although I don't have as much space as you did.
     
  7. Roderick Young

    Thread Starter Member

    Feb 22, 2015
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    Good idea, I'll try to put an SOIC-8 on there. But your little adapter board gave me an idea. I could just put some holes there spaced at 100 mils, and if I ever need something else, could go to a standup board like your adapter.
     
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  8. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    Murphy's Law pretty much dictates that the features available for update/trouble shooting/repair/expansion will always be just a bit fewer than you need.
     
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  9. dl324

    Distinguished Member

    Mar 30, 2015
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    I'm working on a SIP adapter for some P MOSFETs I picked up in a lot of SMT components and found that they were in an SOT-416 package which is about half the size of SOT-23. So I made an adapter that would accommodate both packages:
    upload_2015-10-26_10-55-52.png
     
  10. dl324

    Distinguished Member

    Mar 30, 2015
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    FWIW, I grabbed those pictures from jameco.com. They used to have more variety; so now I'm designing my own.

    The pads for 0603 and 0805 are close enough that you could use the 0805 footprint for both. I'm drawing some SIP adapters that will accommodate 0603, 0805, or 1206 by merging the 3 footprints as I did for my SOT-23/SOT-416 adapter.
     
  11. Roderick Young

    Thread Starter Member

    Feb 22, 2015
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    Thanks, but I'm trying to avoid really tiny stuff. 20 years ago, I could read the numbers on 0603's without glasses, and hand solder 20-mil QFP's. Nowadays, even an 0805 presents a challenge, even with tweezers and a magnifier. All my resistors are 1206, even if there is negligible power running through them.
     
  12. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    I would just put the name of the device, your name and a date, or, add a funny logo.
     
  13. dl324

    Distinguished Member

    Mar 30, 2015
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    Old age and 4 decades of long days staring at computer monitors has taken a toll on my vision. I use a lighted magnifier to read the markings on most small components. Fortunately, my hands are still steady and manipulating 0603 and SOT-416 aren't a problem (yet).
     
  14. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    I have an awesome stereo microscope for doing this kind of stuff. Even with my old eyes, I can place and solder 0402's with ease.

    Luckily, my hands don't shake.
     
  15. RichardO

    Well-Known Member

    May 4, 2013
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    I am interested. Are they straight or right angle? I have a lot of inventory to barter -- what do you need?
     
  16. Roderick Young

    Thread Starter Member

    Feb 22, 2015
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    So many great ideas! This is what I'm finally going with:
    proto-area.GIF
    There wasn't room for a larger SOIC, but I was able to get an 8-pin one on the underside, and connect it to pins on a 100-mil grid. There is one SOT23 footprint, with connections to what might be future base, collector, or emitter resistors. I've got two resistors in series, and two in parallel, plus 3 more footprints connected to nothing to the left (those without reference designators on the silkscreen). Finally, there's one surface mount trim pot. I used minimum width (10-mil) traces throughout, so that they would be easy to cut if the need arose.
     
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