Wake-up for low power application

[Central SUPPORT]

We are working on a very low power device which requires a "wake up" interrupt utilizing a "cost effective" device. I have initially started looking at the LIS3DE which has two interrupt outputs.

We essentially are in an active (VCC is on), with low power consumption waiting for the shock to occur. Once the shock occurs, we need to generate an interrupt to "wake up" the MCU.

We need to have an interrupt occur at 100usecs after sensing the shock and generate the interrupt.

Can you provide a recommendation which of your devices fits these requirements best?

NOTE: This question and answer originated from a customer support case which was handled by us. We regularly review support cases and add any helpful ones here for all to benefit from.

[Central SUPPORT · Accepted solution]

For low power consumption application, please consider using the LIS2DW12. It has a sleep to wake (activity/inactivity) feature. When there is no activity, the sensor will drop down to 12.5Hz ODR. It will continue sample the activity, wake up when threshold is reached, back to previous programmed ODR rate.

In normal operating mode, the sensor operating current can be as low as 0.38uA. It has many operating modes to choose based on your application.

Interrupt generation time depends on ODR, either the one you programmed or the in-active mode ODR

If low cost is a must, you can use LIS3DE. For longevity, please use LIS2DE12 (same feature as LIS3DE, but is newer and smaller). The part has sleep-to-wake feature. When no activity, it goes to sleep (operating at 10Hz ODR). The sensor will wake up when there is activity detected.