MMA7455LT Freescale Semiconductor, MMA7455LT Datasheet - Page 2

• 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

Contents
ELECTRO STATIC DISCHARGE (ESD) ......................................................................................................................................6
PRINCIPLE OF OPERATION ......................................................................................................................................................8
FEATURES ..................................................................................................................................................................................9
LEVEL DETECTION ...................................................................................................................................................................10
THRESHOLD DETECTION FOR MOTION AND FREEFALL CONDITIONS ............................................................................11
PULSE DETECTION ..................................................................................................................................................................12
ASSIGNING, CLEARING & DETECTING INTERRUPTS ..........................................................................................................15
DIGITAL INTERFACE ................................................................................................................................................................16
BASIC CONNECTIONS .............................................................................................................................................................19
REGISTER DEFINITIONS .........................................................................................................................................................21
SOLDERING AND MOUNTING GUIDELINES FOR THE LGA ACCELEROMETER SENSOR TO A PC BOARD ...................29
Sensors
Freescale Semiconductor
Self-Test .........................................................................................................................................................................9
g-Select ..........................................................................................................................................................................9
Standby Mode ................................................................................................................................................................9
Measurement Mode .......................................................................................................................................................9
$18: Control 1 (Read/Write) Setting the Detection Axes for X, Y and Z .......................................................................10
$19: Control 2 (Read/Write) Motion Detection (OR Condition) or Freefall Detection (AND Condition) ........................10
$18: Control 1 (Read/Write): Setting the threshold to be an integer value or an absolute value .................................10
$1A: Level Detection Threshold Limit Value (Read/Write) ...........................................................................................10
CASE 1: Motion Detection ...........................................................................................................................................11
CASE 2: Motion Detection ...........................................................................................................................................11
CASE 3: Freefall Detection ..........................................................................................................................................11
CASE 4: Freefall Detection ..........................................................................................................................................11
$18: Control 1 (Read/Write): Disable X, Y or Z for Pulse Detection .............................................................................12
$19: Control 2 (Read/Write): Motion Detection (OR condition) or Freefall Detection (AND condition) ........................12
CASE 1: Single Pulse Motion Detection: X or Y or Z > Pulse Threshold for Time < Pulse Duration ..........................12
CASE 2: Freefall Detection: X and Y and Z < Pulse Threshold for Time > Latency Time ...........................................13
CASE 3: Double Pulse Detection: X OR Y OR Z > Threshold for Pulse Duration1 < PDTime1, Latency Time, .........14
Clearing the Interrupt Pins: Register $17 .....................................................................................................................15
Detecting Interrupts ......................................................................................................................................................16
I
SPI Slave Interface ......................................................................................................................................................18
Pin Descriptions ...........................................................................................................................................................19
Recommended PCB Layout for Interfacing Accelerometer to Microcontroller .............................................................19
2
C Slave Interface .......................................................................................................................................................16
MMA7455L
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