Eliminate vibrations with noise-canceling waveforms
Focused design to improve RNC system accuracy

STMicroelectronics (ST) is creating a comfortable acoustic vehicle environment with a sensor that supports road noise cancellation (RNC) using Active Noise-Control (ANC) technology.

ST announced on the 18th that it has developed the AIS25BA, which improves the accuracy of the RNC system by utilizing its MEMS (Micro Electro-Mechanical System) IC technology capabilities.

Traditionally, the value of a car has been determined by engine performance, exterior design, and powertrain, but increasingly, the focus is on the comfort of the driver and passengers.

In fact, electric vehicles (EVs) are inherently quieter than internal combustion engine (ICE) vehicles, but vehicle manufacturers are working to reduce interior noise even from wheels and vibrations.

The noise cancellation algorithm works with a series of sensors installed throughout the vehicle to measure ambient sounds and cancel out vibrations with noise-canceling waveforms that act as vibration-blocking (cancelling) sounds.

The AIS25BA sensor has the lowest electrical noise on the market, enabling automotive engineers to create the quietest in-vehicle environment.

Additionally, the RNC system requires fast response and real-time calculation of correction waveforms. It has low latency and wide bandwidth to capture interference frequencies across the sound frequency spectrum relevant to your application.

Their wide temperature range and mechanical robustness also allow them to be deployed in close proximity to the most demanding locations in modern vehicles, such as around engines and electric drives, as well as around wheels and suspensions.

ST's 3-axis accelerometer AIS25BA is designed with a focus on accuracy in RNC systems.

It has an extremely low noise density of 30µg/√Hz in the X and Y axes and 50µg/√Hz in the Z axis, outperforming the nearest competitor by up to 58%.

With such excellent noise performance and a frequency response extended to 2, it covers the entire spectrum related to in-car noise cancellation.

Likewise, it is designed with a total sensor latency of 266µs, allowing the system to generate noise-cancelling signals in real time.

Additionally, it has a Time-Division Multiplex (TDM) digital interface, which allows for synchronization of the outputs of multiple acceleration sensors installed in the system to measure vibration throughout the vehicle.

The full measurement range is selectable up to ±7.7g, providing ample margin even for the typically strong vibrations of the application. The supply voltage range is 1.71 V to 1.99 V.

The AIS25BA is AEC-Q100 compliant and is available now in a 14-lead LGA package measuring 2.5mm x 2.5mm x 0.86mm, priced at $3.90 in quantities of 1,000.

Sample requests can be confirmed through the ST Korea branch.

“In today’s digital age, the smart way to create quieter interior environments and thus safer and more enjoyable journeys is not to block out unwanted sounds, but to eliminate them,” said Simone Ferri, Marketing Director of the MEMS Subgroup of STMicroelectronics’ Analog, MEMS and Sensors Group. “With the shift to hybrid and electric vehicles, where road noise can be significantly affected, ST’s AIS25BA accelerometer offers exceptional value to system designers.”