Datasheet

± 8g / 16g / 32g / 64g Tri-axis
Digital Accelerometer
Specifications
PART NUMBER:
KX134-1211
Rev. 1.0
31-Jul-2019
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Terminology
g
A unit of acceleration equal to the acceleration of gravity at the earth's surface.
2
8.91
s
m
g =
One thousandth of a g (0.0098 m/ s
2
) is referred to as 1 milli-g (1 mg).
Sensitivity
The sensitivity of an accelerometer is the change in output per unit of input acceleration at nominal VDD and
temperature. The term is essentially the gain of the sensor expressed in counts per g (counts/g) or LSB’s per g
(LSB/g). Occasionally, sensitivity is expressed as a resolution, i.e. milli-g per LSB (mg/LSB) or milli-g per count
(mg/count). Sensitivity for a given axis is determined by measurements of the formula:
( )
g
gOutpu tgOutput
ySensit iv it
2
1@1@ −−+
=
The sensitivity tolerance describes the range of sensitivities that can be expected from a large population of sensors
at room temperature and over life. When the temperature deviates from room temperature (25ºC), the sensitivity
will vary by the amount shown in Table 1.
Zero-g offset
Zero-g offset or 0-g offset describes the actual output of the accelerometer when no acceleration is applied. Ideally,
the output would always be in the middle of the dynamic range of the sensor (content of the OUTX, OUTY, OUTZ
registers = 00, expressed as a 2’s complement number). However, because of mismatches in the sensor, calibration
errors, and mechanical stress, the output can deviate from 00. This deviation from the ideal value is called 0-g
offset. The zero-g offset tolerance describes the range of 0-g offsets of a population of sensors over the operating
temperature range.
Self-test
Self-test allows a functional test of the sensor without applying a physical acceleration to it. When activated, an
electrostatic force is applied to the sensor, simulating an input acceleration. The sensor outputs respond
accordingly. If the output signals change within the amplitude specified in Table 1, then the sensor is working
properly and the parameters of the interface chip are within the defined specifications.