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High sensitivity MEMS acceleration sensor

The new, triaxial BMA180 acceleration sensor from Bosch Sensortec measures 3x3x0.9mm in its LGA housing and reacts sensitively to even the smallest of movements. In the 2g measuring range, minimal accelerations of 0.00025g and tilt changes in the field of gravity of 0.25º can be reliably detected using its 14bit measurement dynamic. With its high sensitivity and good linearity, the sensor covers the entire scope of applications for g sensors – from simple step counters in pedometers up to precision applications, such as in GPS navigation support and in digital spirit levels. Product developers have the benefit of programming the technical characteristics according to their specific needs. For instance, the measuring range can be switched between 1g and 16g in seven steps – also during operations. Within a measuring range, the variation in sensitivity is low: in the 2g range, it is only 1.5% with a temperature drift TCS (temperature coefficient of sensitivity) of 0.01%/Kelvin.

The internal digital filter's programming, with 8 x low-pass, 1 x high-pass, and 1 x band-pass, offers designers many options for internal signal conditioning. As is appropriate for high signal resolution, the integrated automatic zero balancing functions with high exactitude, the residual zero-g offset remains below 5mg. This is especially relevant for navigation applications: when using a BMA180, they can achieve a high degree of accuracy in determining position. The offset temperature drift (TCO) is minimal, at 0.25mg/Kelvin. This is easily perceived in all applications that involve large temperature variations: for example, a video projector equipped with a sensor and electromechanical levelling can project an image on the projection surface that remains undistorted, despite the increasing heat. Independent from factory calibration, values such as sensitivity, offset, TCO and TSO can be calibrated within the final product so that the good characteristics of the sensor can be fully utilised in every application.