MMA7455LT Freescale Semiconductor, MMA7455LT Datasheet - Page 30

• Manufacturer Part Number: MMA7455LT
• Description: Board Mount Accelerometers 3-AXIS DIGITAL 2 4 8G
• Manufacturer: Freescale Semiconductor

Specifications of MMA7455LT

• Sensing Axis: X, Y, Z
• Acceleration: 2 g, 4 g, 8 g
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 2.4 V
• Supply Current: 400 uA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Sensitivity: 64 LSB/g
• Package / Case: LGA-14
• Output Type: Digital
• Acceleration Range: ± 2g, ± 4g, ± 8g
• No. Of Axes: 3
• Sensor Case Style: LGA
• No. Of Pins: 14
• Supply Voltage Range: 2.4V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Filter Terminals: SMD
• Rohs Compliant: Yes
• Ic Interface Type: I2C, SPI
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Information provided here is based on experiments executed on LGA devices. They do not represent exact conditions present
at a customer site. Hence, information herein should be used as a guidance only and process and design optimizations are
recommended to develop an application specific solution. It should be noted that with the proper PCB footprint and solder stencil
designs the package will self-align during the solder reflow process.
The following are the recommended guidelines to follow for mounting LGA sensors for consumer applications.
PCB MOUNTING RECOMMENDATIONS
1.
2.
3.
4.
5.
30
MMA7455L
Top metal pattern
under package area
Top metal pattern
under package area
Figure 19. Incorrect PCB Top Metal Pattern Under
The PCB land should be designed with Non Solder Mask Defined (NSMD) as shown in
No additional metal pattern underneath package as shown in
PCB land pad is 0.9 mm x 0.6 mm which is the size of the package pad plus 0.1 mm as shown in
The solder mask opening is equal to the size of the PCB land pad plus an extra 0.1 mm as shown in
The stencil aperture size is equal to the PCB land pad – 0.025mm.
Pad Dimension by Package
Figure 21. Recommended PCB Land Pad, Solder Mask, and Signal Trace Near Package Design
0.8 mm
Via structure under
Via structure under
package area
Package
0.5 mm
Cu: 0.9 x 0.6 mm sq.
OVERVIEW OF SOLDERING CONSIDERATIONS
LGA package w/ solder
Example of 2 layer PCB
PCB top metal layer
PCB land pattern - NSMD
SM opening = PCB land pad + 0.1mm
= 1.0 x 0.7mm sq.
Figure
Figure 20. Correct PCB Top Metal Pattern Under Package
20.
Wider trace
Signal trace near
package: 0.1mm width
and min. 0.5mm length
are recommended.
Wider trace can be
continued after these.
Figure
21.
Freescale Semiconductor
Figure
Figure
21.
21.
Sensors