Using FIFO modes
AN4450
20/26
DocID025978 Rev 1
Figure 9. Hardware digital filter
The digital filter reduces the pressure noise level to 0.010 hPa rms (1 Pa at 1 sigma) and
allows to reduce the internal ADC HW average, reducing power consumption while keeping
the same pressure noise level.
Filter enabling and suggested configuration
To reduce power consumption while keeping a low noise figure, the recommendation is to
reduce the pressure and temperature averaging, reduce ODR to minimum and enable the
digital filter (FIFO).
For example:
RES_CONF(0x10) = 0x05 (set AVGT=16, AVGP=32, or less)
FIFO_CTRL (0x2E) = 0xC1 (Set FIFO Mean mode with average on 2 samples or more,
up to 0xDF)
CTRL_REG2 (0x21) = 0x40 (FIFO enabled, decimation disabled)
CTRL_REG1 (0x20) = 0x90 (ODR = 1 Hz, power-on device)
In this way, the power consumption at 1 Hz is reduced from the typical 26.4 µA to about 4.5
µA with a pressure noise of 0.01 hPa rms.
