User's Manual

LE910 V2 HARDWARE USER GUIDE 1VV0301200 Rev.2 Preliminary • 2015-08-04 68 of 81
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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 following figure).
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.
Inhibit area for micro-via