Datasheet
Preliminary Data Sheet SHT3x-ARP
www.sensirion.com November 2014 - 0.9 8/11
5.2 Package Outline
Figure 11 Dimensional drawing of SHT3x-ARP sensor package
Parameter
Symbol
Min
Nom.
Max
Units
Comments
Package height
A
0.8
0.9
1
mm
Leadframe height
A3
0.2
mm
Not shown in the drawing
Pad width
b
0.2
0.25
0.3
mm
Package width
D
2.4
2.5
2.6
mm
Center pad length
D2
1
1.1
1.2
mm
Package length
E
2.4
2.5
2.6
mm
Center pad width
E2
1.7
1.8
1.9
mm
Pad pitch
e
0.5
mm
Pad length
L
0.3
0.35
0.4
mm
Max cavity
S
1.5
mm
Only as guidance. This value includes all tolerances,
including displacement tolerances. Typically the
opening will be smaller.
Center pad marking
T1xT2
0.3x45°
mm
indicates the position of pin 1
Table 7 Package outline
5.3 Land Pattern
Figure 12 shows the land pattern. The land pattern is
understood to be the metal layer on the PCB, onto
which the DFN pads are soldered.
The solder mask is understood to be the insulating
layer on top of the PCB covering the copper traces. It is
recommended to design the solder mask as a Non-
Solder Mask Defined (NSMD) type. For NSMD pads,
the solder mask opening should provide a 60 μm to 75
μm design clearance between any copper pad and
solder mask. As the pad pitch is only 0.5 mm we
recommend to have one solder mask opening for all 4
I/O pads on one side.
For solder paste printing it is recommended to use a
laser-cut, stainless steel stencil with electro-polished
trapezoidal walls and with 0.1 or 0.125 mm stencil
thickness. The length of the stencil apertures for the I/O
pads should be the same as the PCB pads. However,
the position of the stencil apertures should have an
offset of 0.1 mm away from the center of the package.
The die pad aperture should cover about 70 – 90 % of
the die pad area –thus it should have a size of about
0.9 mm x 1.6 mm.
For information on the soldering process and further
recommendation on the assembly process please
consult the Application Note
HT_AN_SHTxx_Assembly_of_SMD_Packages , which
can be found on the Sensirion webpage.
E
D
S
A
e
b
D2
E2
L
T1 x T2