PMMA7450LR2 Freescale Semiconductor, Inc, PMMA7450LR2 Datasheet - Page 22

• Manufacturer Part Number: PMMA7450LR2
• Description: ?2g/?4g/?8g Three Axis Low-g Digital Output Accelerometer
• Manufacturer: Freescale Semiconductor, Inc

for mounting LGA sensors for consumer applications.
PCB MOUNTING RECOMMENDATIONS
22
MMA7450L
The following are the recommended guidelines to follow
Top metal pattern
under package area
1. The PCB land should be designed with Non Solder
2. No additional metal pattern underneath package as
Figure 20. Incorrect PCB Top Metal Pattern Under
3. PCB land pad is 0.9mm x 0.6mm which is the size of
Mask Defined (NSMD) as shown in
shown in
the package pad plus 0.1mm as shown below in
Package
Figure 22. Recommended PCB Land Pad, Solder Mask, and Signal Trace Near Package Design
0.8 mm
Figure
Via structure under
21.
Package
0.5 mm
Cu: 0.9 x 0.6 mm
LGA package w/ solder
Figure
Example of 2 layer PCB
PCB top metal layer
SM opening = PCB land pad + 0.1mm
= 1.0 x 0.7mm sq.
Figure 23. Stencil Design Guidelines
PCB land pattern -
22.
sq.
0.575m
Figure 21. Correct PCB Top Metal Pattern Under Package
4. The solder mask opening is equal to the size of the
5. The stencil aperture size is equal to the PCB land pad
0.625m
Figure
PCB land pad plus an extra 0.1mm as shown in
Figure
– 0.025mm. Also note that for the 4 corner pads the
aperture size must be larger for solder balancing as
shown in
is recommended.
Wider trace
Signal trace near
package
22.
22.
Figure 23
Package
footprint
Stencil openings for 4
corner pads are bigger
than others, Refer to
next drawing.
Signal trace near
package: 0.1mm width
and min. 0.5mm length
are recommended. Wider
trace can be continued
after these.
and
Figure
Freescale Semiconductor
24. A 6mil thick stencil
Sensors