Freescale Semiconductor
Data Sheet: Technical Data
An Energy-Efficient Solution by Freescale
Document Number: MMA8452Q
Rev. 5, 07/2012
3-Axis,
12-bit/8-bit
Digital Accelerometer
The MMA8452Q is a smart low-power, three-axis, capacitive micromachined
accelerometer with 12 bits of resolution. This accelerometer is packed with
embedded functions with flexible user programmable options, configurable to two
interrupt pins. Embedded interrupt functions allow for overall power savings
relieving the host processor from continuously polling data.
The MMA8452Q has user selectable full scales of ±2g/±4g/±8g with high-pass
filter filtered data as well as non-filtered data available real-time. The device can
be configured to generate inertial wakeup interrupt signals from any combination
of the configurable embedded functions allowing the MMA8452Q to monitor
events and remain in a low power mode during periods of inactivity. The
MMA8452Q is available in a 3 mm by 3 mm by 1 mm QFN package.
Features
•
•
•
•
•
•
•
•
•
1.95V to 3.6V supply voltage
1.6V to 3.6V interface voltage
±2g/±4g/±8g dynamically selectable full-scale
Output Data Rates (ODR) from 1.56 Hz to 800 Hz
99
μg/√Hz
noise
12-bit and 8-bit digital output
I
2
C digital output interface
Two programmable interrupt pins for six interrupt sources
Three embedded channels of motion detection
— Freefall or Motion Detection: 1 channel
— Pulse Detection: 1 channel
— Transient Detection: 1 channel
– Orientation (Portrait/Landscape) detection with set hysteresis
– Automatic ODR change for Auto-WAKE and return to SLEEP
– High-Pass Filter Data available real-time
– Self-T
est
– RoHS compliant
– Current Consumption: 6
μA
– 165
μA
MMA8452Q
Top and Bottom View
16 PIN QFN
3 mm by 3 mm by 1 mm
CASE 2077-02
Top View
VDD
14
13
12
11
10
9
6
SDA
7
SA0
8
NC
NC
GND
INT1
GND
INT2
Shipping
Tray
Tape and Reel
NC
16
VDDIO
BYP
NC
SCL
GND
1
2
3
4
5
NC
15
Typical Applications
•
eCompass applications
•
Static orientation detection (Portrait/Landscape, Up/Down, Left/Right, Back/
Pin Connections
Front position identification)
•
Notebook, eReader and Laptop Tumble and Freefall Detection
•
Real-time orientation detection (virtual reality and gaming 3D user position feedback)
•
Real-time activity analysis (pedometer step counting, freefall drop detection for HDD, dead-reckoning GPS backup)
•
Motion detection for portable product power saving (Auto-SLEEP and Auto-WAKE for cell phone, PDA, GPS, gaming)
•
Shock and vibration monitoring (mechatronic compensation, shipping and warranty usage logging)
•
User interface (menu scrolling by orientation change, pulse detection for button replacement)
ORDERING INFORMATION
Part Number
MMA8452QT
MMA8452QR1
Temperature Range
-40°C to +85°C
-40°C to +85°C
Package Description
QFN-16
QFN-16
© 2012 Freescale Semiconductor, Inc. All rights reserved.
Contents
1
2
Block Diagram and Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Soldering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Mechanical and Electrical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Mechanical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3 I
2
C Interface Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.4 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1 Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2 Zero-g Offset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3 Self-Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1 Device Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.2 8-bit or 12-bit Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.3 Low-Power Modes vs. High-Resolution Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4 Auto-WAKE/SLEEP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.5 Freefall and Motion Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.6 Transient Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.7 Pulse Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.8 Orientation Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.9 Interrupt Register Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.10 Serial I
2
C Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Register Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.1 Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.2 Portrait/ Landscape Embedded Function Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.3 Motion and Freefall Embedded Function Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
6.4 Transient (HPF) Acceleration Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.5 Single, Double and Directional Pulse-Detection Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.6 Auto-WAKE/SLEEP Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6.7 Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
6.8 User Offset Correction Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3
4
5
6
Related Documentation
The MMA8452Q device features and operations are described in a variety of reference manuals, user guides, and application
notes. To find the most-current versions of these documents:
1.
2.
3.
Go to the Freescale homepage at:
http://www.freescale.com/
In the Keyword search box at the top of the page, enter the device number MMA8452Q.
In the Refine Your Result pane on the left, click on the Documentation link.
MMA8452Q
2
Sensors
Freescale Semiconductor, Inc.
1
Block Diagram and Pin Description
Internal
OSC
Clock
GEN
Embedded
DSP
Functions
INT1
INT2
VDD
VDDIO
VSS
X-axis
Transducer
Y-axis
Transducer
Z-axis
Transducer
C to V
Converter
12-bit
ADC
I
2
C
SDA
SCL
Freefall
and Motion
Detection
Transient
Detection
(i.e., fast motion,
transient)
Orientation with
Set Hysteresis
and Z-lockout
Shake Detection
through
Motion
Threshold
Single, Double
& Directional
Pulse Detection
Auto-WAKE/Auto-SLEEP Configurable with debounce counter and multiple motion interrupts for control
MODE Options
Low Power
Low Noise + Power
High Resolution
Normal
MODE Options
Low Power
Low Noise + Power
High Resolution
Normal
ACTIVE Mode
WAKE
Auto-WAKE/SLEEP
ACTIVE Mode
SLEEP
Figure 1. Block Diagram
Z
Earth Gravity
X
1
13
1
Y
9
5
(TOP VIEW)
DIRECTION OF THE
DETECTABLE ACCELERATIONS
(BOTTOM VIEW)
Figure 2. Direction of the Detectable Accelerations
MMA8452Q
Sensors
Freescale Semiconductor, Inc.
3
Figure 3
shows the device configuration in the six different orientation modes. These orientations are defined as the following:
PU = Portrait Up, LR = Landscape Right, PD = Portrait Down, LL = Landscape Left, BACK and FRONT side views. There are
several registers to configure the orientation detection and are described in detail in the register setting section.
Top View
PU
Pin 1
Earth Gravity
Side View
LL
Xout @ 0g
Yout @ -1g
Zout @ 0g
LR
BACK
Xout @ 0g
Yout @ 0g
Zout @ -1g
PD
Xout @ -1g
Yout @ 0g
Zout @ 0g
Xout @ 1g
Yout @ 0g
Zout @ 0g
FRONT
Xout @ 0g
Yout @ 0g
Zout @ 1g
Xout @ 0g
Yout @ 1g
Zout @ 0g
Figure 3. Landscape/Portrait Orientation
1.6V - 3.6V
VDDIO
1.95V - 3.6V
VDD
4.7μF
16
NC
15
NC
14
VDD
1
2
VDDIO
BYP
NC
SCL
NC
GND
13
12
11
10
9
VDDIO
VDDIO
0.1μF
0.1μF
3
4
5
MMA8452Q
INT1
GND
SDA
SA0
NC
4.7kΩ
4.7kΩ
GND
INT2
6
7
8
INT1
SCL
SDA
INT2
SA0
Figure 4. Application Diagram
MMA8452Q
4
Sensors
Freescale Semiconductor, Inc.
Table 1. Pin Descriptions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Pin Name
VDDIO
BYP
NC
SCL
GND
SDA
SA0
NC
INT2
GND
INT1
GND
NC
VDD
NC
NC
Description
Power Supply for IO pins (1.62V - 3.6V)
Bypass capacitor (0.1
μF)
Leave open. Do not connect.
I
2
C Serial Clock
Connect to Ground
I C Serial Data
I
2
C Least Significant Bit of the Device I
2
C Address
Internally not connected (can be GND or VDD)
Inertial Interrupt 2
Connect to Ground
Inertial Interrupt 1
Connect to Ground
Internally not connected (can be GND or VDD)
Internal Power Supply (1.95V - 3.6V)
Internally not connected (can be GND or VDD)
Internally not connected (can be GND or VDD)
2
Pin Status
Input
Input
Open
Open Drain
Input
Open Drain
Input
Input
Output
Input
Output
Input
Input
Input
Input
Input
The device power is supplied through VDD line. Power supply decoupling capacitors (100 nF ceramic plus 4.7 µF bulk, or a
single 4.7 µF ceramic) should be placed as near as possible to the pins 1 and 14 of the device.
The control signals SCL, SDA, and SA0 are not tolerant of voltages more than VDDIO + 0.3V. If VDDIO is removed, the control
signals SCL, SDA, and SA0 will clamp any logic signals with their internal ESD protection diodes.
The functions, the threshold and the timing of the two interrupt pins (INT1 and INT2) are user programmable through the I
2
C
interface. The SDA and SCL I
2
C connections are open drain and therefore require a pullup resistor as shown in the application
diagram in
Figure 4.
1.1
Soldering Information
The QFN package is compliant with the RoHS standard. Please refer to AN4077.
MMA8452Q
Sensors
Freescale Semiconductor, Inc.
5
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