MEV-50D-R MEMS传感器

Murata has launched a MEMS rate sensor (gyro) which features ‘excellent’ performance characteristics for the automotive market. The MEV-50D-R supports accurate dead-reckoning performance for car navigation devices, and is also aimed at GPS modules, salite antennas and other applications such as toys, including for example a high-performance radio-control helicopter.

The sensor features the second-generation of Murata’s technology – the first generation was used in Murata’s famous bicycle-riding robots, Murata boy and the unicycle-riding Murata Girl.

High temperature drift performance makes signal processing easy – there is no need to adjust for temperature drift in software. Temperature drift across the entire operating range, -40C to 85C, is just 0.6 deg/s. Materials used in the construction of the rate sensor help to ensure the stable temperature performance of the device. Single-crystal silicon is used for the core MEMS vibrator, while the MEMS element is composed of silicon and pyrex gl*, which have very similar temperature expansion coefficients, increasing stability.

Another key factor for rate sensors used in car navigation systems is the start-up drift. It t*ically takes several minutes after the system is switched on for a GPS signal to be acquired, so dead-reckoning is commonly used during this time. The MEV-50D-R exhibits particularly impressive start-up drift; just 0.1 deg/s between 0.5s and 5 minutes after start-up.

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

The MEMS element uses anodic bonding creating a seal which achieves much better performance than the current industry standard of 10-9 Pa m3/s. The seal did not change its efficiency during air tank/heat shock tests with 2000 cycles of -55C to +125C (30 min/30 min). This high level of seal allows Murata’s MEMS technology to be applied under harsh conditions such as automotive.

The MEV-50C-R measures 10mm x 6.2mm x 2.9mm and weighs just 0.3g (maximum). Maximum angular velocity is +/-70deg/s. The sensor’s ‘unique’ ladder structure means the part is not influenced by external physical noise (shock or vibration), and thus exhibits more accurate angular-rate information than competing parts, says the company.