BMA120
Digital, triaxial acceleration sensor
Bosch Sensortec
General description
The BMA120 is a triaxial, low-g acceleration sensor
with digital interfaces, aiming for low-power consumer
market applications.
The BMA120 allows measurement of accelerations in
3 perpendicular axes. An evaluation circuitry converts
the output of a three-channel micromechanical accele-
ration sensing structure that works according to the
differential capacitance principle.
The BMA120 senses tilt, motion, shock and vibration
in cell phones, handhelds, computer peripherals,
man-machine interfaces, virtual reality features and
game controllers.
BMA120 target applications
Display profile switching (e.g. portrait / landscape)
Tap / Double-tap function
Menu scrolling
Gaming
Advanced power management for mobile devices
Drop protection for warranty logging
Shock detection
Pedometer / step counting
Sensor operation
The BMA120 represents a new generation of digital
acceleration sensors. The BMA120 integrates a multi-
tude of features that facilitates its use especially in
the area of motion detection applications, such as
device orientation detection, gaming, HMI and menu
browser control.
Key features BMA120
User programmable g-range and bandwidth
Low-power consumption
SPI (3-wire / 4-wire) and I²C interface
User programmable interrupt engine
Ultra-low-power self-wake-up mode
Very small package
RoHS compliant, halogen-free
Digital input/output
Supply voltage
(V
DD
/ V
DDIO
)
Temperature range
LGA package
-20°C … +70°C
3 mm x 3 mm x 0.9 mm
Resolution
Nonlinearity
Zero-g offset
Bandwidth
6bit
Sensitivity
(calibrated)
Technical data
Sensitivity axes
Measurement range
BMA120
x/y/z
±2g, ±4g, ±8g, ±16g
(switchable via SPI / I²C)
2g: 16LSB/g
4g:
8g:
16g:
8LSB/g
4LSB/g
2LSB/g
±2% FS
±100 mg (typ.)
50Hz, 75Hz, 150Hz,
250Hz, 600Hz, 1kHz
(switchable via SPI / I²C)
SPI & I²C, interrupt pin
1.8V (±10%)
The BMA 120 is highly configurable in order to give
the designer full flexibility when integrating the sensor
into his system. All features can be set by software via
the digital interface.
As already introduced with the successful BMA150
and SMB380 acceleration sensors, also for the
BMA120 g-ranges and bandwidths can be user pro-
grammed via the serial digital interface. Here the user
can choose between an I
2
C and an SPI (3-wire/4-wire)
interface modes.
One of the key elements of the BMA120 is the intelli-
gent interrupt engine that gives the hard- and software
designer full control. Various motion detection scena-
rios can be identified by the BMA120 and signaled to
the system via a simple interrupt pin. By using the
digital serial interface, the exact details of the motion
event that triggered the interrupt can be read-out from
the BMA120.
62.5mg (±2g range)
2
Bosch Sensortec
BMA120
Pin configuration (top view)
Pin 1
identifier
CAPY
Following motion detection scenarios are supported
by the interrupt engine:
Any-motion (slope) detection
Tap sensing
11
CAPZ
V
DDD
SD
X
SDO
12
CAPX
V
DD
GND
INT
CSB
1
2
3
4
5
6
PS
Orientation change recognition
Low-g / high-g detection
Data-ready
Self-wake-up
The interrupts can be configured by the user and thus
BMA120
top view
(pads not visible)
10
9
8
7
SC
X
perfectly support the integration of the BMA120 into
the user’s system environment.
Another important feature of the BMA120 acceleration
sensor is the power management module. This modu-
le allows for optimizing the sensor’s power consump-
Pin
No.
1
2
3
4
5
6
7
8
9
Name
Function
tion in-line with the specific user requirements. Thus,
it is not necessary to operate the sensor at full power
for all application scenarios all the time. For some
uses cases the power consumption drastically shrinks
to just a fraction of what would be required in full
performance mode.
The power modes the BMA120 supports are:
CAPX
V
DD
GND
INT
CSB
PS
SCL
SCK
SDO
SDA,
SDI,
SDO
V
DDD
CAPZ
CAPY
Do not connect! (recommended)
Power supply analog
Shared ground
Interrupt output
SPI chip-select
Protocol select pin
I
2
C(SCL) / SPC(SCK) serial clock
SPI serial data output
I C / SPI serial data in/out
2
Mode
Wake-up
time
Current
consumption
@ 1.8 V V
DD
0 µA
1 µA (typ.)
2 µA (typ.)
430 µA
Power-off
Suspend
Low-power (sleep)
Full performance
only 1 ms
≤ 400 µs
≤ 400 µs
–
10
11
12
Power supply digital
Do not connect! (recommended)
Do not connect! (recommended)
The BMA120 also features self-test capability, allowing
for testing of the complete signal evaluation path
including the micromachined sensor structure and
the evaluation ASIC.
Headquarters
Bosch Sensortec GmbH
Gerhard-Kindler-Strasse 8
72770 Reutlingen · Germany
Telephone +49 7121 3535 900
Fax +49 7121 3535 909
contact@bosch-sensortec.com
www.bosch-sensortec.com
Specification subject to change without notice
Doc.-Number: BST-BMA120-FL000-00 / Version_1.1_102009
© Bosch Sensortec GmbH reserves all rights in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on
to third parties. BOSCH and the symbols are registered trademarks of Robert Bosch GmbH, Germany.
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