NL865B1 HW Design Guide
1VV0301450 Rev. 1
Page
57
of
72
2017-11-20
It is not recommended to place via or micro-via not covered by solder resist in an area of
0.3 mm around the pads unless it carries the same signal of the pad itself (see figure
below).
Holes in pad are allowed only for blind holes and not for through holes.
Recommendations for PCB pad surfaces:
Finish
Layer Thickness (um)
Properties
Electro-less Ni / Immersion
Au
3 –7 / 0.05 – 0.15
good solder ability
protection,
high shear force values
The PCB must be able to resist the higher temperatures which are occurring at the lead-
free process. This issue should be discussed with the PCB-supplier. Generally, the
wettability of tin-lead solder paste on the described surface plating is better compared to
lead-free solder paste.
It is not necessary to panel the application’s PCB, however in that case it is suggested to
use milled contours and predrilled board breakouts; scoring or v-cut solutions are not
recommended.
Stencil
Minimum stencil thickness recommended is 125um
Solder paste
We recommend using only “no clean” solder paste in order to avoid the cleaning of
the modules after assembly.
