10
Figure 11. Solder stencil aperture
Figure 12. Keep-out area
Adjacent Land Keep out and Solder Mask Areas
Adjacent land keep out is the maximum space occupied
by the unit relative to the land pattern. There should be
no other SMD components within this area. The minimum
solder resist strip width required to avoid solder bridging
adjacent pads is 0.2mm.It is recommended that two
fiducial crosses be placed at mid length of the pads for
unit alignment. Also do take note that there should not
be any electrical routing with the component placement
compartment.
Note:
Wet/Liquid Photo-imaginable solder resist/mask is recommended
Recommended Metal solder Stencil Aperture
It is recommended that only a 0.152 mm (0.006 inch) or
a 0.127 mm (0.005 inch) thick stencil be used for solder
paste printing. This is to ensure adequate printed solder
paste volume and no shorting. See Table 1 below the
drawing for combinations of metal stencil aperture and
metal stencil thickness that should be used. Aperture
opening for shield pad is 3.05 mm x 1.1 mm as per land
pattern.
Table 1. Combinations of metal stencil aperture and metal
stencil thickness
Stencil
thickness,
t (mm)
Aperture size (mm)
Length,
l
Width,
w
0.152 1.60+/-0.05 0.55+/-0.05
0.127 1.92 0.55+/-0.05
Dim. mm
h 4.15
l11
k 5.5
j 3.5
Recommended land pattern
Figure 10. Land Pattern
Solder Pad, Mask and Metal Stencil
Appendix A: HSDL-9100 SMT Assembly Application Note
PCBA
Land Pattern
Solder Mask
Metal stencil for
solder paste printing
Stencil Aperture
l
w
t
Apertures as per
Land Dimensions
Mounting Center
j
h
Component placement
Solder Mask
k
l
Figure 9. Stencil and PCBA
Solder / stencil opening for each pad is 2.4mm x0.6mm
7.7
7.1
2.4
2.1
0.5
0.6
0.525
0.6
0.6
2.75
