Dear Sir,
Please let us know if soldering a wire to an SMT pad without PTH is an appropriate method. Additionally, if there are any IPC standards or recommendations regarding this, kindly share them with us.
Best regards,
Logesh. P
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I believe soldering a wire directly to an SMT pad without a PTH is not ideal because SMT pads aren’t designed to handle the mechanical stress of a wire connection. This could lead to pad damage or reliability issues over time.
According to IPC standards like IPC 7711/7721 and IPC A-610, it’s better to use a PTH for mechanical strength or reinforce the wire with strain relief methods like adhesives. If soldering to an SMT pad is unavoidable in your case, make sure you have additional support to prevent stress on the pad.
Hope that helps.
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Since I tend to do things like that for repairs I wanted to check carefully when giving you answer. Every source I checked (IPC, EIA, even Hacker News) carefully recommended NOT to do this. The main reason cited by everyone was the tendency to rip up pads with only minor strain on the wires.
Even when using a thru-hole pad the standards require minimum length and permanent anchoring of the wire to the PCB.
Finally, one source said it might be acceptable - sometimes. Shown is a clip from NASA using the technique. So while I can’t recommend it, if you use it anchor your wires, keep them short, and remember it’s more acceptable as a repair or rework option.
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Thank you, Allan!