Fitness monitoring wearables are a large part of a growing variety of products and applications require the high accuracy sensing of static and dynamic air pressure.
As these applications are typically found in battery operated devices, it is also essential to combine the high accuracy with optimised low-power operation and reliability across a broad range of operating conditions.
Many existing small form-factor MEMS (Micro Electro-Mechanical System) pressure sensors are built around piezo-resistive measurement techniques. In these cases, the flexing of a diaphragmin relation to changes in pressure is sensed via a strain sensor.
However, piezo-resistive sensing elements are particularly susceptible to variation with temperature changes and they do not respond linearly to temperature.
For this reason, piezo-resistive sensors have a need for more complex calibration compared to a capacitive element.
In addition, resistive measurement can represent a significant drain on power – a particularly important consideration when the target application is battery-powered and operating lifetime is critical.
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