STMicroelectronics AIS25BA 3-axis accelerometer

Click2Contact

STMicroelectronics is enabling more acoustically comfortable cars with its new sensor for road-noise cancellation (RNC) through active noise-control (ANC) techniques. ST has leveraged its competencies in micro electro-mechanical system (MEMS) ICs to give the AIS25BA 3-axis accelerometer the characteristics to enhance RNC system accuracy. The sensor is designed to provide minimal electrical noise, which helps vehicle engineers achieve a calm in-car environment. It also has the fast response/low latency needed by the RNC system to calculate corrective waveforms in real time as well as wide bandwidth to capture disturbances across the full spectrum of sound frequency relevant for the application. Its wide temperature range and mechanical robustness allow placement in harsh places inside today’s vehicles: near the engine or electric drive as well as close to wheels and suspension.

The accelerometer is engineered to prioritise RNC system accuracy. At 30 µg/√Hz in X and Y axes and 50 µg/√Hz in the Z axis, it has low noise density. The accelerometer’s noise performance enables the frequency response to extend to 2 and hence covers the spectrum relevant for in-car noise cancellation. Similarly, the total sensor latency of 266 µs is engineered for leaving the system plenty of time to generate noise-cancellation signals in real time.

The sensor also has a time-division multiplex (TDM) digital interface that enables the system to synchronise the outputs from multiple accelerometers installed to measure vibrations throughout the vehicle. This audio-friendly interface also facilitates easy connection to other types of data bases adopted in the automotive industry. The full-scale measurement range is selectable up to ±7.7 g, giving plenty of margin with respect to the intense vibrations typical of the application. The supply-voltage range is 1.71 to 1.99 V. The AIS25BA is compliant with AEC-Q100 and is available now in a 14-lead 2.5 x 2.5 x 0.86 mm LGA package.