DESIGN
T&M
Surviving the extremes: understanding shock and vibration in MEMS sensors MEMS-based accelerometers are increasingly deployed in harsh environments where mechanical stress is not just expected but constant. Two critical specifications often found in accelerometer data sheets are shock survivability and vibration tolerance. While they may appear similar, they serve distinct purposes and are tested differently. Understanding these differences is essential for selecting the right sensor for your application.
gross failures such as beam breakage in the MEMS structure but can also include system-level issues like wire bond detachment or die cracking Vibration tolerance: surviving the everyday Vibration tolerance, in contrast, measures the sensor’s ability to function reliably under continuous or repetitive vibrations – a common condition in many industrial and transportation applications. • Test standard: usually MIL-STD-883 Method 2007 (or manufacturer-de- fined)
Shock survivability: withstanding the unexpected
By Pablo del Corro, Product Applications Engineer, Analog Devices
Shock survivability refers to an accelerometer’s ability to endure
non-repetitive, high magnitude acceleration events. These events typically occur during the component (IC) handling, assembly, or accidental drops.
• Test Standard: IEC 60068-2-27
• Test method: half-sine wave pulses of defined magnitude and duration, applied across all axes • Purpose: ensures the device remains functional after rare but extreme shocks
• Test method: continuous random
vibration within a specified amplitude and frequency range
• Failure mechanism: typically results in
Figure 1. (a) Representation of a MEMS accelerometer structure. (b) Zoomed-in section on one of the stoppers. The stoppers help protect the MEMS structure under high shock events.
36 ELECTRONICSPECIFIER.COM
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