NXP Semiconductors
Data sheet: Technical data
Document Number: MMA8451Q
Rev. 10.3, 02/2017
MMA8451Q, 3-axis,
14-bit/8-bit
digital accelerometer
MMA8451Q
Top and bottom view
The MMA8451Q is a smart, low-power, three-axis, capacitive, micromachined
accelerometer with 14 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. There is access to both
low-pass filtered data as well as high-pass filtered data, which minimizes the data
analysis required for jolt detection and faster transitions. The device can be
configured to generate inertial wakeup interrupt signals from any combination of
the configurable embedded functions allowing the MMA8451Q to monitor events
and remain in a low-power mode during periods of inactivity. The MMA8451Q is
available in a 16-pin QFN, 3 mm x 3 mm x 1 mm package.
Features
•
•
•
•
•
•
•
•
•
1.95 V to 3.6 V supply voltage
1.6 V to 3.6 V interface voltage
±2
g/±4 g/±8 g
dynamically selectable full scale
Output data rates (ODR) from 1.56 Hz to 800 Hz
99
μg/√Hz
noise
14-bit and 8-bit digital output
I
2
C digital output interface
Two programmable interrupt pins for seven interrupt sources
Three embedded channels of motion detection
— Freefall or motion detection: one channel
— Pulse detection: one channel
— Jolt detection: one channel
Orientation (portrait/landscape) detection with programmable hysteresis
Automatic ODR change for auto-wake and return to sleep
32-sample FIFO
High-pass filter data available per sample and through the FIFO
Self-test
Current consumption: 6
μA
to 165
μA
16-pin QFN
3 mm x 3 mm x 1 mm
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
DNC
SCL
GND
1
2
3
4
5
NC
15
•
•
•
•
•
•
Typical Applications
•
•
•
•
•
•
•
•
Pin connections
E-compass applications
Static orientation detection (portrait/landscape, up/down, left/right, back/front
position identification)
Notebook, e-reader, 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, tap detection for button replacement)
Ordering information
Part number
MMA8451QT
MMA8451QR1
Temperature range
–40 °C to +85 °C
–40 °C to +85 °C
Package description
QFN-16
QFN-16
© NXP Semiconductors N.V. 2017
Contents
Block Diagram and Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Mechanical and Electrical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Mechanical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3 I2C interface characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.4 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1 Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2 Zero-g offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3 Self-test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4 System Modes (SYSMOD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5 Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.1 Device calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.2 8-bit or 14-bit data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3 Internal FIFO data buffer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.4 Low-power modes vs. high-resolution modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.5 Auto-wake/sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.6 Freefall and motion detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.7 Transient detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.8 Tap detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.9 Orientation detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.10 Interrupt register configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.11 Serial I
2
C interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6 Register Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.1 Data registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.2 32-sample FIFO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.3 Portrait/landscape embedded function registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6.4 Motion and freefall embedded function registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.5 Transient (HPF) acceleration detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6.6 Single, double and directional tap detection registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
6.7 Auto-wake/sleep detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
6.8 Control registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
6.9 User offset correction registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
7 Printed Circuit Board Layout and Device Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
7.1 Printed circuit board layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
7.2 Overview of soldering considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
7.3 Halogen content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
8 Package Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
8.1 Tape and reel information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
8.2 Package description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9 Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Related documentation
The MMA8451Q 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.
Go to the MMA8453Q web page at
http://www.nxp.com/products/:MMA8451Q.
Click the Documentation tab.
Sensors
NXP Semiconductors N.V.
MMA8451Q
2
1
Block Diagram and Pin Description
Internal
OSC
Clock
GEN
14-bit
ADC
Embedded
DSP
Functions
INT1
INT2
VDD
VDDIO
VSS
X-axis
Transducer
Y-axis
Transducer
Z-axis
Transducer
C to V
Converter
I
2
C
SDA
SCL
32 Data Point
Configurable
FIFO Buffer
with Watermark
Freefall
and Motion
Detection
Transient
Detection
(i.e., fast motion,
jolt)
Enhanced
Orientation with
Hysteresis
and Z-lockout
Shake Detection
through
Motion
Threshold
Single, Double,
and Directional
Tap Detection
Auto-wake/Auto-sleep configurable with debounce counter and multiple motion interrupts for control
MODE Options
Low Power
Low Noise + Low Power
High Resolution
Normal
MODE Options
Low Power
Low Noise + Low 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
MMA8451Q
Sensors
NXP Semiconductors N.V.
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 @ 0
g
Yout @ –1
g
Zout @ 0
g
LR
BACK
Xout @ 0
g
Yout @ 0
g
Zout @ –1
g
Xout @ –1
g
Yout @ 0
g
Zout @ 0
g
PD
Xout @ 1
g
Yout @ 0
g
Zout @ 0
g
FRONT
Xout @ 0
g
Yout @ 0
g
Zout @ 1
g
Xout @ 0
g
Yout @ 1
g
Zout @ 0
g
Figure 3. Landscape/portrait orientation
1.6V - 3.6V
Interface Voltage
1.95V - 3.6V
VDD
4.7μF
16
NC
15
NC
14
VDD
1
2
VDDIO
BYP
NC
GND
13
12
11
10
9
VDDIO
VDDIO
0.1μF
0.1μF
3
4
5
DNC
NC
SCL
MMA8451Q
INT1
GND
SDA
SA0
4.7kΩ
4.7kΩ
GND
NC
INT2
6
7
8
INT1
SCL
SDA
INT2
SA0
Figure 4. Application diagram
MMA8451Q
4
Sensors
NXP Semiconductors N.V.
Table 1. Pin description
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Pin name
VDDIO
BYP
DNC
SCL
GND
SDA
SA0
NC
INT2
GND
INT1
GND
NC
VDD
NC
NC
Internal power supply (1.62 V to 3.6 V)
Bypass capacitor (0.1
μF)
Do not connect to anything, leave pin isolated and floating.
I
2
C serial clock, open drain
Connect to ground
I
2
C serial data
I
2
C least significant bit of the device I
2
C address, I
2
C 7-bit address = 0x1C (SA0 = 0), 0x1D (SA0 = 1).
Internally not connected
Inertial interrupt 2, output pin
Connect to ground
Inertial interrupt 1, output pin
Connect to ground
Internally not connected
Power supply (1.95 V to 3.6 V)
Internally not connected
Internally not connected (can be GND or VDD)
Description
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 + 0.3 V. 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.
MMA8451Q
Sensors
NXP Semiconductors N.V.
5
ADI参考电路
