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Calculate SMD and NSMD pad dimensions for BGA package - KBA233772

Chelladurai
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Calculate SMD and NSMD pad dimensions for BGA package - KBA233772

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Consider the following table to calculate the dimensions for SMD and NSMD pad types when designing hardware with BGA package FAB024 for optimum board-level reliability. See Figure 1.

Solder mask defined (SMD) pad type

Non-solder mask defined (NSMD) pad type

Solder mask opening = min. Solder ball size (1:1)

 

These values should be such that PCB metal pad (Ball land pad) > Solder ball size > Solder mask opening

Solder mask opening = (Solder ball diameter x (0.8 ~ 1.0)) + 0.15 mm

The values should be such that PCB metal pad (Ball land pad) < Solder ball size < Solder mask opening

For NSMD, solder mask opening is 0.15 mm larger than solder pad to secure enough space for excess solder.

 

Note: These values depend on the designer’s decision on the solder ball diameter size when processing; note that these are only recommendations. Take into account the BGA pad pitch to make sure that the solder balls are clearly apart from each other to prevent short circuits.

Chelladurai_0-1631534993967.png

Figure 1

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‎Sep 13, 2021 05:12 AM
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