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SOD-323 SOD323 land pattern, which one?

Former Member

mornin'

 

Have any of you ever used SOD-323 package? If so, what is your preferred

land pattern for SOD-323, reflow? I have looked at several different

manufacturers, and all of them suggest different land patterns for

reflow. The pad size varies the most. For example, ON Semi has the pads

at .63mm x .83mm while Diode Inc. has the pads at .65mm x 1.35mm. The

land pattern I used for my prototype was from Vishay, which set the pad

size at .6mm x .6mm. It seems too small. BTW, The diode is a Schottky,

BAT54.

 

Any insights will be greatly appreciated,

 

Tony

 

  • tony wrote:

    mornin'

     

    Have any of you ever used SOD-323 package? If so, what is your preferred

    land pattern for SOD-323, reflow? I have looked at several different

    manufacturers, and all of them suggest different land patterns for

    reflow. The pad size varies the most. For example, ON Semi has the pads

    at .63mm x .83mm while Diode Inc. has the pads at .65mm x 1.35mm. The

    land pattern I used for my prototype was from Vishay, which set the pad

    size at .6mm x .6mm. It seems too small. BTW, The diode is a Schottky,

    BAT54.

     

    Any insights will be greatly appreciated,

     

    Tony

     

    Apparently most manufacturer show the outdated IPC-782 land patterns.

    Looking at the more current IPC-7351A land patterns, something like the

    one suggested by Diodes Inc. is now preferred. I can see why, as there

    is more pad for the heel of the part's bent lead to grab on to, and more

    at the toe to ease re-work. I settled on 1.35mm x .7mm, pads spaced

    2.4mm from center.

     

    Tony

     

  • in reply to Former Member

    Hi Tony & Tony,

     

    I just lost the 3rd LPQF-100 uC in a design I am working on!  It turns out that our PCB guy used the 6 x 6mm pads for numerous SOD-323 diodes, including an input protection 4.1V zener.  One of the Schottkeys fell off while I was probing it and the Zener had about 30k Ohm resitance in series with it.  I though the Zener was bad so I unsoldered one side an it fell off the PCB.  The other 6x6mm pad had nice dark gray, grainy solder on it (whic was the mysterious 30 k Ohm).  This led me to search all of the SOD-323 suggested footprints I could find.  Like Tony #1, I found many different sizes including NXP and Vishay who specify the 6x6mm.  I thoroughly agree with Tony #2 about the largest land pattern.  At worst case the diode won't perfectly self align and may be a bit askew, but it will stay solderd on!   Thanks for the info.  I, and many of the semiconductor makers, are making our own footprints and not trust the IPC.

     

    Imre