Datasheet

ADXL345 Data Sheet
Changes in noise performance, self-test response, and supply
current are discussed elsewhere throughout the data sheet. For
noise performance, the Noise Performance section should be
reviewed. The Using Self-Test section discusses both the operation
of self-test over voltage, a square relationship with supply voltage,
as well as the conversion of the self-test response in g’s to LSBs.
Finally, Figure 33 shows the impact of supply voltage on typical
current consumption at a 100 Hz output data rate, with all other
output data rates following the same trend.
OFFSET PERFORMANCE AT LOWEST DATA RATES
The ADXL345 offers a large number of output data rates and
bandwidths, designed for a large range of applications. However,
at the lowest data rates, described as those data rates below 6.25 Hz,
the offset performance over temperature can vary significantly
from the remaining data rates. Figure 54, Figure 55, and Figure 56
show the typical offset performance of the ADXL345 over
temperature for the data rates of 6.25 Hz and lower. All plots
are normalized to the offset at 100 Hz output data rate; therefore,
a nonzero value corresponds to additional offset shift due to
temperature for that data rate.
When using the lowest data rates, it is recommended that the
operating temperature range of the device be limited to provide
minimal offset shift across the operating temperature range.
Due to variability between parts, it is also recommended that
calibration over temperature be performed if any data rates
below 6.25 Hz are in use.
0
20
40
60
80
100
120
140
25 35 45 55 65 75 85
NORMALIZED OUTPUT (LSB)
TEMPERATURE (°C)
0.10Hz
0.20Hz
0.39Hz
0.78Hz
1.56Hz
3.13Hz
6.25Hz
07925-056
Figure 54. Typical X-Axis Output vs. Temperature at Lower Data Rates,
Normalized to 100 Hz Output Data Rate, V
S
= 2.5 V
0
20
40
60
80
100
120
140
25 35 45
55 65 75 85
NORMALIZED OUTPUT (LSB)
TEMPERATURE (°C)
0.10Hz
0.20Hz
0.39Hz
0.78Hz
1.56Hz
3.13Hz
6.25Hz
07925-057
Figure 55. Typical Y-Axis Output vs. Temperature at Lower Data Rates,
Normalized to 100 Hz Output Data Rate, V
S
= 2.5 V
–20
0
20
40
60
80
100
120
140
25 35 45
55 65 75 85
NORMALIZED OUTPUT (LSB)
TEMPERATURE (°C)
0.10Hz
0.20Hz
0.39Hz
0.78Hz
1.56Hz
3.13Hz
6.25Hz
07925-058
Figure 56. Typical Z-Axis Output vs. Temperature at Lower Data Rates,
Normalized to 100 Hz Output Data Rate, V
S
= 2.5 V
Rev. E | Page 34 of 40