Bosch Sensortec
BMA140
Analog, triaxal acceleration sensor
General description
The BMA140 is an analog, triaxial low-g acceleration
sensor for consumer market applications, available in
a super-flat land-grid array (LGA) package with a very
small footprint of 3mm x 3mm and a height of merely
0.9mm. It allows measurements of static as well as
dynamic accelerations. Due to its three perpendicu-
lar axes it gives the absolute orientation in a gravity
field and enables free-fall detection.
The BMA140 is a two-chip arrangement, which com-
bines an application-specific integrated circuit (ASIC)
with a three-channel silicon accelerometer, to form a
true micro electro mechanical system (MEMS).
This concept and the advanced micromachining tech-
nology have proven their robustness and reliability
in more than 150 million Bosch MEMS sensors per
year. The modular ASIC design provides the flexibili-
ty to react quickly to customer needs for additional
sensor functionality in the future.
The BMA140 provides three parallel analog output
signals in a ±4g acceleration range. In addition to the
parallel X, Y and Z output signals there is the option to
multiplex any axis to a single supplementary output
pin in a freely customized manner.
Leveraging its ultra-low power consumption and its
wake-up feature the BMA140 senses tilt, motion,
shock and vibration in advanced gaming console
applications and all kind of mobile, personal com-
munication and entertainment devices.
BMA140 applications based on low-g sensing
Gaming f
Virtual reality f
Sports- and life-style wear f
Handhelds f
Healthcare f
Cell phones f
Navigation f
Electronic compass compensation f
Key features BMA140
Triaxial, analog low-g sensor with three f
parallel outputs
±4g range f
Ultra low power consumption f
Power-saving stand-by mode f
Fast wake-up time f
Very wide power supply range f
Additional multiplexed serial analog output f
Internal filtering capability f
On-chip gain and offset compensation f
Self-test capability f
Super-flat, small footprint LGA package f
RoHS compliant f
Technical data BMA140
Sensitive axes
Measurement range
Package
Sensitivity
(factory trimmed)
Non-linearity
Cross axis sensitivity
Zero-g offset
(factory trimmed)
Zero-g offset tempera-
ture drift
RMS-noise
Bandwidth
(1st order LP filtering)
Supply voltage
Current consumption
Idle current
Wake-up time
Temperature range
x/y/z
±4g
LGA, 3 mm x 3 mm x
0.9 mm
VDD/10 [V/g]
±0.5 % FS (typ.)
0.2 % (typ.)
±150 mg (max.)
±1 mg/K (typ.)
220 μg/√Hz
1.5 kHz
1.8 … 3.5 V
200 μA
(typ., normal mode)
0.9 μA
(max.,stand-by mode)
1 msec (typ.)
-40 °C … +85 °C
BMA140
© 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.
Specification subject to change without notice Version_1.0_022008
Bosch Sensortec
2
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
Sensor operation
The BMA140 provides three parallel analog output
sig nals in a ±4g acceleration range. All acceleration
signals are permanently available on three indepen-
dent analog pads through 33kΩ resistors on each pad.
For each axis, an independent analog 1.5kHz
1st-order low-pass filter is included to provide pre-
conditioning of the measured acceleration signal.
In combination with the integrated 33kΩ resistors,
the corner frequency of this filter can easily be
customized by the use of external capacitors.
Additional signal preconditioning steps are per-
formed by a digital-to-analog converter for offset
and gain correction purposes with a subsequent
signal amplification. All output signals are fully
ratio-metric.
With an acceleration range of ±4g the BMA140 provi-
des a sensitivity of 300mV/g at 3.0V supply voltage
(VDD/10) and 220µg/√Hz as a typical RMS noise
level. The typical current consumption is only 200µA
in normal operation mode.
In addition to the parallel X, Y and Z output signals
there is the option to multiplex any axis to one single
supplementary output pin in a freely customized
manner, thus requiring only one A/D channel.
Furthermore, the BMA140 can be switched into
stand-by mode via supplementary selection pins. In
this mode the sensor module features an ultra-low
current consumption of only 0.9µA at maximum. The
return from stand-by mode to normal mode takes
less than 1 millisecond wake up time.
The BMA140 is ready to use due to test and calibra-
tion at factory level. All calibration parameters, e.g.
for offset and sensitivity, are stored in an internal
EEPROM.
The BMA140 also features full self-test capability for
all three axes. It provides full testing of the complete
signal evaluation path including the MEMS accelera-
tionsensing element and the evaluation ASIC.
Pin No. Name Function
1 VDD1 Supply voltage
2 VDD2 Supply voltage
3 GND 1 Ground connection
4 GND 2 Ground connection
5ST Self test activation
6 SEL.1 Multiplexer selection
7TEST Do not connect
8AZ Z acceleration output
9AY Y acceleration output
10 AX X acceleration output
11 AMUX Multiplex serial output
12 SEL.0 Multiplexer selection
Package and pin configuration
11
1
8
4
10
2
7
5
9
3
12 6
Pin 1
identifier
top view
(pads not visible)
SEL.0 SEL.1
AMUX X out Y out Z out TEST
VDD1 STVDD2 GND1 GND2
