CMA3000 Datasheet, PDF (11/18 Pages) VTI technologies – 3-axis accelerometer

CMA3000 Assembly Instructions
Note that the stencil openings should always be matched to the selected PWD pad design and
solder paste type for the optimal solder paste release. Furthermore, the stencil material and
method of forming those have an effect on solder paste release.
5.4 Paste Printing
The paste printing speed should be adjusted according to the solder paste specifications. Care
should be taken during paste printing in order to ensure correct paste amount, shape, position, and
other printing characteristics. Neglecting any of these can cause open solder joints, bridging,
solder balling, or other unwanted soldering results.
5.5 Component Picking
The CMA3000 component can be picked from the carrier tape using vacuum nozzles. Pick up
nozzles are available in various sizes and shapes to suit a variety of different component
geometries. It is recommended to that different pick up nozzles are tested to find the best one
suited for the purpose. The polarity of the part on tape is presented in section 4.1.
In case manual handling of the CMA3000 component is required, special attention should be paid
on the handling procedures. Delicate handling is a necessity as exposed silicon and glass surfaces
on the CMA3000 component are very sensitive to mechanical handling. Handling with metallic
tweezers should be forbidden. However, manual handling is not recommended.
5.6 Component Placement
The CMA3000 components must be placed onto PWB accurately according to their geometry.
Reflowable solder spheres provide self-alignment for the component, which will help with accurate
positioning. Positioning the packages manually is not recommended.
Placement can be done with typical automatic component pick & place machinery capable of
placing similar sized components. Recognition of the packages automatically by a vision system
enables correct centering of the packages. The Z placement should be carefully controlled as too
high force or overdriving during the component placement may damage the component and cause
misalignment. Maximum assembly force is 4 N. Locally the mounting pressure should not exceed 1
MPa.
5.7 Reflow Soldering
A forced convection reflow oven is recommended to be used for soldering CMA3000 components.
The reflow profile used for soldering the CMA3000 should always follow the solder paste
manufacturer's specifications and recommended profile. The ramp-up rate should typically be less
than 3°C/second. The reflow maximum peak temperature (measured from the component body)
should not exceed 260°C and the minimum temperature (measured from the solder joints) should
be higher than 230°C. The ramp down rate should be 6°C/second max. Figure 10 presents a
general forced convection reflow solder profile with the typical phases of a reflow process. Please
refer to IPC/JEDEC J-STD-020C table 5-2 and figure 5-1 for details. Recommended max number
of reflow cycles is 3.
VTI Technologies Oy
www.vti.fi
PRELIMINARY
Subject to changes
TN68
11/18
Rev.09