MEMS rate sensor for the automotive market

Murata has launched the MEV-50C-R, a MEMS rate sensor that supports accurate dead-reckoning performance for car navigation devices and with other applications in satellites and radio-controlled toys.

Signal processing for the software is made easier the device's capable temperature drift performance, which across the entire operating range of -40 to 85C is 0.6 degrees.

Single-crystal silicon is used for the core MEMS vibrator, while the MEMS element is composed of silicon and pyrex glass, which have very similar temperature expansion coefficients, to increase stability.

The MEV-50C-R's start-up drift is 0.1 degrees between 0.5s and 5 min after start up.

High linearity (0.5 per cent across the operating range of angular velocity) and low cross-axis sensitivity (+/-5 per cent) make it possible to follow winding roads as the sensor output follows the change of angular rate precisely.

According to the company, anodic bonding in the MEMS element creates a seal that delivers better performance than the current industry standard of 10-9 Pa m3/s.

This seal did not change its efficiency during air tank/heat shock tests with 2000 cycles of -55 to +125C (30 min/30 min), meaning Murata's MEMS technology can be applied under harsh conditions such as automotive.

Its 'ladder' structure means the part is not influenced by external physical noise (shock or vibration), allowing for accurate angular-rate information.

The MEV-50C-R measures 10.0 x 6.2 x 2.9mm and weighs 0.3g (maximum).

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