μClamp1211Z
Final Datasheet Rev 5.1
Revision Date 2/22/2017
www.semtech.com
4 of 7
Semtech
Application Information
Assembly Guidelines
The small size of this device means that some care must
be taken during the mounting process to insure reliable
solder joints. The gure at the right details Semtech’s
recommended mounting pattern. Recommended
assembly guidelines are shown in Table 1. Note that
these are only recommendations and should serve only
as a starting point for design since there are many factors
that aect the assembly process. Exact manufacturing
parameters will require some experimentation to get the
desired solder application.
Solder Stencil
Stencil design is one of the key factors which will
determine the volume of solder paste which is deposited
onto the land pad. The area ratio of the stencil aperture
will determine how well the stencil will print. The area
ratio takes into account the aperture shape, aperture
size, and stencil thickness. A minimum area ratio of 0.66
is preferred for the subject package. The area ratio of a
rectangular aperture is given as:
Area Ratio = (L * W )/ (2 * (L + W) * T)
Where:
L = Aperture Length
W = Aperture Width
T = Stencil Thickness
Semtech recommends a stencil with square aperture
and rounded corners for consistent solder release. The
stencil should be laser cut with electropolished nish. A
stencil thickness of 0.075mm (0.003”) is recommended.
A 0.100mm (0.004”) stencil may be used, however the
stencil opening may need to be increased slightly to
achieve the desired area ratio to ensure proper solder
coverage on the pad.
Assembly Parameter Recommendation
Solder Stencil Design Laser Cut, Electro-Polished
Aperture Shape Rectangular with
Rounded Corners
Solder Stencil Thickness 0.075mm (0.003”) or
0.100mm (0.004”)
Solder Paste Type Type 4 Size Sphere or
Smaller
Solder Reow Prole Per JEDEC J-STD-020
PCB Solder Pad Design Solder Mask Dened
PCB Pad Finish OSP or NiAu
All Dimensions are in mm.
Land Pad.
Stencil opening Component
Stencil Opening
Land Pattern
Component
0.270
0.250
0.320
0.175
0.620
0.675
Recommended Mounting Pattern
Table 1 - Assembly Guidelines
