LSM303AGR Datasheet, PDF (21/68 Pages) STMicroelectronics – ultra-low-power 3D accelerometer and 3D magnetometer

LSM303AGR
4
Functionality
Functionality
4.1
4.1.1
Magnetometer
Magnetometer power modes
The LSM303AGR magnetometer provides two different power modes: high-resolution and
low-power modes.
The tables below summarize the selection of the low-pass filter and current consumption of
the operating modes.
When the low-pass filter is enabled, the bandwidth is reduced while noise performance is
improved without any increase in power consumption.
CFG_REG_B_M
[LPF]
0 (disable)
1 (enable)
Table 10. Digital low-pass filter
(CFG_REG_A_M [LP = 0])
high-resolution mode
(CFG_REG_A_M [LP = 1])
low-power mode
BW [Hz]
Noise RMS [mg]
BW [Hz]
Noise RMS [mg]
ODR/2
4
ODR/2
8.5
ODR/4
3
ODR/4
6
Table 11. Current consumption of operating modes
ODR
Current consumption (μA)
Current consumption (μA)
(Hz) _{(CFG_REG_A_M [LP] = 0) - high-resolution (CFG_REG_A_M [LP] = 1) - low-power}
10
100
25
20
200
50
50
500
125
100
1000
250
The following table summarizes the turn-on time of the magnetometer in the two different
power modes with the offset cancellation function enabled or disabled (see Section 4.1.2:
Magnetometer offset cancellation).
Table 12. Operating mode and turn-on time
Operating mode
Turn-on time
CFG_REG_A_M[LP] CFG_REG_A_M[OFF_CANC = 0] CFG_REG_A_M[OFF_CANC = 1]
0 (high-resolution)
1 (low-power)
9.4 ms
6.4 ms
9.4 ms + 1/ODR
6.4 ms + 1/ODR
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