MMA8491Q
Rev. 2.1 — 26 April 2016
3-Axis Multifunction Digital Accelerometer
Data sheet: Technical data
COMPANY PUBLIC
1
General description
The MMA8491Q is a low voltage, 3-axis low-g accelerometer housed in a 3 mm x 3 mm
QFN package. The device can accommodate two accelerometer configurations, acting
2
as either a 45° tilt sensor or a digital output accelerometer with I C bus.
•
As a 45° tilt sensor, the MMA8491Q device offers extreme ease of implementation by
using a single line output per axis.
•
As a digital output accelerometer, the 14-bit ±8
g
accelerometer data can be read from
the device with a 1 mg/LSB sensitivity.
The extreme low power capabilities of the MMA8491Q will reduce the low data rate
current consumption to less than 400 nA per Hz.
2
Features and benefits
•
•
•
•
•
•
•
•
•
Extreme low power, 400 nA per Hz
Ultra-fast data output time, ~700 μs
V
DD
supply range of 1.95 V to 3.6 V
3 mm x 3 mm, 0.65 mm pitch with visual solder joint inspection
±8
g
full-scale range
14-bit digital output, 1 mg/LSB sensitivity
1
Output Data Rate (ODR), implementation based from < 1 Hz to 800 Hz
2
I C digital interface
3-axis, 45° tilt outputs
3
Typical applications
•
•
•
•
Smart grid: tamper detect
Anti-theft
White goods tilt
Remote controls
1
The ODR for this device is user defined by the period of the Enable pulsed signal. The maximum
recommended frequency of the Enable signal or the ODR that can be achieved for this device is 800 Hz.
NXP Semiconductors
MMA8491Q
3-Axis Multifunction Digital Accelerometer
4
Ordering information
Part Number
Temperature Range
–40 to +85 °C
–40 to +85 °C
–40 to +85 °C
QFN 12
QFN 12
QFN 12
Table 1. Ordering information
Package
Tray
Shipping
1000 pc / Tape & Reel
5000 pc / Tape & Reel
MMA8491QT
MMA8491QR1
MMA8491QR2
5
Related documentation
The MMA8491Q 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. Go to the NXP homepage at:
http://www.nxp.com/
2. In the Keyword search box at the top of the page, enter the device number
MMA8491Q. In the Refine Your Result pane on the left, click on the Documentation
link.
6
Block diagram
Figure 1. Block Diagram
7
Pinout
MMA8491Q is hosted in a 12-pin 3 mm x 3 mm QFN package. Ten pins are used for
functions; two pins are unconnected. Refer to
Table 2
for complete pin descriptions and
functions.
MMA8491Q
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2016. All rights reserved
Data sheet: Technical data
COMPANY PUBLIC
Rev. 2.1 — 26 April 2016
2 / 28
NXP Semiconductors
MMA8491Q
3-Axis Multifunction Digital Accelerometer
MMA8491Q
NC
12
NC
11
Byp
V
DD
SDA
EN
1
2
3
4
5
6
10
9
8
7
Xout
Yout
Zout
Gnd
SCL
Transparent top view
Figure 2. Pin connection diagram
Table 2. Pin descriptions
Pin
1
Symbol
Byp
Function
Description
Gnd
Pin status
Output
Internal regulator The internal regulator voltage of 1.8 V is present on this
output capacitor pin. Connect to external 0.1 μF bypass capacitor.
connection
Power Supply
2
V
DD
Device power is supplied through the V
DD
line. Power
Input
supply decoupling capacitors should be placed as near as
possible to pin 1 of the device.
I C Slave Data Line, open drain
Input/Output
2
•
7-bit I C device address is 0x55
2
•
The SDA and SCL I C connections are open drain, and
therefore usually require a pull-up resistor
The Enable pin fully turns on the accelerometer system
when it is pulled up to logic high. The accelerometer
system is turned off when the Enable pin is logic low.
I C Slave Clock Line, open drain
Ground
Ground
2
2
3
SDA
I C Data
2
4
EN
Enable pin
Input
5
6
7
8
SCL
Gnd
Gnd
Zout
I C Clock
Ground
Ground
2
Input
Ground
Ground
9
Yout
Push-pull Z-Axis
•
Output is high when acceleration is > 0.688
g
(axis is | Output
Tilt Detection
φ| > 45°).
Output
•
Output is low when acceleration is ≤ 0.688
g
(axis is |φ|
≤ 45°).
Push-pull Y-Axis
Output
•
These pins are push-pull output pins.
Tilt Detection
Output
Push-pull X-Axis
Tilt Detection
Output
No internal
connection
No internal
connection
No internal connection
No internal connection
Output
10
Xout
11
12
NC
NC
MMA8491Q
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2016. All rights reserved
Data sheet: Technical data
COMPANY PUBLIC
Rev. 2.1 — 26 April 2016
3 / 28
NXP Semiconductors
MMA8491Q
3-Axis Multifunction Digital Accelerometer
8
Recommended application diagram
Figure 3. V
DD
connects to power supply and EN is pulsed
To ensure the accelerometer is fully functional, connect the MMA8491Q as suggested in
Figure 3.
•
A capacitor must be connected to the Bypass pin (pin 1) to assist the internal voltage
regulator. It is recommended to use a 0.1 μF capacitor. The capacitor should be placed
as near as possible to the Bypass pin.
•
The device power is supplied through the V
DD
line. The power supply decoupling
capacitor should be placed as close as possible to the V
DD
pin.
–
Use a 1.0 or 4.7 μF capacitor when the V
DD
and EN are not tied together.
–
When V
DD
and EN are tied together, use a 0.1 μF capacitor. The 0.1 μF capacitor
value has been chosen to minimize the average current consumption while still
maintaining an acceptable level of power supply high frequency filtering.
•
Both ground pins (pins 6 and 7) must be connected to ground.
2
•
When the I C communication line is used, use a pull-up resistor to connect to line SDA
and SCL. The SCL line can be driven by a push-pull driver, in which case, no pull-up
resistor is necessary. If SDA and SCL pins are not used, then they should be tied to
ground.
9
Sensing direction and output response
The MMA8491Q has three tilt detection outputs: Xout, Yout, and Zout. The following
figure shows the output results at the six different orientation positions.
MMA8491Q
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2016. All rights reserved
Data sheet: Technical data
COMPANY PUBLIC
Rev. 2.1 — 26 April 2016
4 / 28
NXP Semiconductors
MMA8491Q
3-Axis Multifunction Digital Accelerometer
Top view
Portrait Up
Pin
1
Gravity
Xout @ 0
g
Yout @ –1
g
Zout @ 0
g
Side view
Back
Xout @ 0
g
Yout @ 0
g
Zout @ –1
g
Landscape Left
Landscape Right
Front
Xout @ 0
g
Yout @ 0
g
Zout @ 1
g
Xout @ –1
g
Yout @ 0
g
Zout @ 0
g
Portrait Down
Xout @ 1
g
Yout @ 0
g
Zout @ 0
g
Z
X
Xout @ 0
g
Yout @ 1
g
Zout @ 0
g
Y
(Top view)
Reference frame for acceleration measurement
Figure 4. Sensitive axes orientation and output response to ±1
g
(gravity) stimulus
10 Mechanical and electrical specifications
10.1 Absolute maximum ratings
Absolute maximum ratings are the limits the device can be exposed to without damage.
Functional operation at absolute maximum rating is not guaranteed.
Although this device contains circuitry to protect against damage due to high static
voltage or electrostatic fields, it is advised that normal precautions be taken to avoid
application of any voltage higher than the maximum-rated voltage.
Table 3. Absolute maximum ratings
Symbol
g
max
V
DD
D
drop
T
AGOC
T
STG
Analog supply voltage
Drop test
Operating temperature
Storage temperature
Rating
Maximum acceleration (all axes, 100 μs)
Min
—
–0.3
—
–40
–40
Max
10 000
3.6
1.8
+85
+125
Unit
V
V
m
°C
°C
Table 4. ESD and latch-up protection characteristics
Symbol
V
HBM
V
MM
MMA8491Q
Rating
Human body model (HBM)
Machine model (MM)
All information provided in this document is subject to legal disclaimers.
Value
±2000
±200
Unit
V
V
© NXP B.V. 2016. All rights reserved
Data sheet: Technical data
COMPANY PUBLIC
Rev. 2.1 — 26 April 2016
5 / 28
