Specifications

BMA180
Preliminary data sheet
Bosch Sensortec
Rev. 1.0 Page 46 / - proprietary information - 06 March 2009
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Specifications within this document are preliminary and subject to change without notice. Document is not intended for publication.
7.10 Performance settings
As performance settings offset, gain (sensitivity), TCO and TCS are considered.
7.10.1 Gain trimming (sensitivity trimming)
Gains of the sensor (temperature and acceleration for x-, y- and z-axis) are calibrated at
production line. Corresponding bit widths are shown below:
gain_t: Gain trimming for temperature (5 bits).
gain_z: Gain trimming for Z axis (7 bits).
gain_y: Gain trimming for Y axis (7 bits).
gain_x: Gain trimming for X axis (7 bits).
The above codes are “offset binary” coded. For instance for gain_x trimming code 1000000 is
the middle code for no trimming and codes for most negative correction to most positive one
are: 0000000, 0000001... 0111111, 1000000, 1000001… 1111110, 1111111.
Attention:
Customer is able to recalibrate sensitivity. If this is done including EEPROM writing, the initial
calibration values are lost, thus care has been taken.
7.10.2 Offset trimming
Offsets of the sensor (temperature and acceleration for x-, y- and z-axis) are calibrated at
production line. Corresponding bit widths are shown below:
offset_t : Offset trimming for temperature (7 bits).
offset_z: Offset trimming for Z axis (12 bits).
offset_y Offset trimming for Y axis (12 bits).
offset_x Offset trimming for X axis (12 bits).
The above codes are “offset binary” coded. For instance for offset_z trimming of z-axis, code
100000000000 is the middle code for no trimming and codes for most negative correction to
most positive one are: 000000000000, 000000000001... 011111111111, 100000000000,
100000000001… 111111111110, 111111111111.
Attention:
Customer is able to recalibrate sensitivity. If this is done including EEPROM writing, the initial
calibration values are lost, thus care has been taken.