Q
The ST LIS3DH, Bosch BMA250, Freescale MMA845xQ states as low as 2uA best case
power, which seems equivalent to the XL362, so what’s the big deal?
A
To achieve its 2 µA, the ST LIS3DH (and all similar accelerometers) has to turn
itself off most of
the time, and wake up to take a sample only about once every second.
This method of operation causes them to miss a lot of acceleration information
while they sleep. ST’s 2 µA sounds great, but because of the way it is
implemented, it cannot capture the full window of real time human
motion without raising its power consumption considerably.
The ADXL362, in contrast, is on ALL THE TIME and, for the same 2 µA, reports
100 samples per second of acceleration data. We have a video to demonstrate the
difference visually.
In some applications, it is enough for the accelerometer to only poll
acceleration once or a few times per second. For these applications, the
ADXL362 provides a wake-up mode that consumes only 270 nA: just over an eighth
of the current consumed by the LIS3DH.