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Bending a SIP package

Discussion in 'Electronic Design' started by JJ, Jun 25, 2007.

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  1. JJ

    JJ Guest

    Hi,

    I have an IC with a 23-Pin SIP package (http://
    eportal.apexmicrotech.com/mainsite/pdf/EX.pdf). The problem is that
    the available package is vertical, and I need it horizental.
    To solve this, I am thinking about, first, slodering the IC, then
    bending it down. However, I am afarid that some of the pins might ge
    disconneted, and the IC is expenisve.

    Does somebody have some experince with this?

    Thanks,
    JJ
     
  2. D from BC

    D from BC Guest

    On occasion I create pseudo-SMD parts from through-hole parts.
    For example, I'll take a 14pin dips and turn it into a SMD.

    I've noticed that typically the metal used with IC's cannot handle
    repeated bending before snapping.

    After a single 90 bend, I wouldn't be surprised if under a microscope
    metal tearing can be seen at the bend..

    I'll guess you have 1 shot at getting the bend right... Once bent, do
    not correct or adjust or these's increased risky of rips.

    I prebend my parts before soldering to get the bend in the preferred
    location and to get a 90 bend on a forming jig...

    Just pushing over the part after soldering can have too much bend
    radius..
    D from BC
     
  3. Bending pins, yes. But I would bend the pins first, and
    then solder. This will trap a lot less push and pull
    between individual pins.
     
  4. D from BC wrote:
    (snip)
    The risk is having too little bend radius. Bending the pins
    over a curved surface really helps distribute the stretching
    forces along more of the pin,, rather than having all the
    bend take place at the weakest point.
     
  5. Meat Plow

    Meat Plow Guest

    Use the old sip as a model and bend it in a hobby vice in between a couple
    pieces of wood. You really have basically one shot so make it count.

    And yes I've done this several times with 100% success.
     
  6. D from BC

    D from BC Guest

    There's a "just right" bend radius :)

    I've pushed over some soldered parts with so much bend radius, I can't
    get 90 deg..the part makes contact with the PCB and then springs up.
    D from BC
     
  7. As I said, the bend should be formed in unsoldered leads
    (using as much of the part that will not be soldered as
    possible), so the part drops into the holes and lies flat
    before it is soldered. The bend should not take place at
    the point where the leads neck down to fit the holes, but
    only at the wider part. Just as DIP lead frames are
    pre-bent between the case and the necked down spot.
     
  8. Bend and form the legs *before* you solder it.
    And once bent, don't move them again.
    Keep the pins in the staggered arrangement.
    Make sure the device is physically attached to the PCB (or heatsink)
    before soldering.

    Dave.
     
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