A novel MEMS-based gyro sensor device for car navigation systems has been released by Murata. Constructed as a System in Package (SiP) component, this microelectromechanical system (MEMS) device contains a silicon based vibration component and custom designed integrated circuit for the capacitive sensor circuitry. The two chips are mounted on a ceramic substrate, and then hermetically sealed in a ceramic surface mount package.
Both devices are manufactured using proven and cost-effective production processes, to provide high reliability and superior performance at a low cost. From the OEM’s perspective, Murata’s MEV-50A-R gyro sensor is a compact, hermetically sealed, surface mount, ceramic device contained in a fully RoHS compliant package measuring just 10mm x 10mm, with a profile of 3.3mm. It will operate over the –40oC to +85oC temperature range, making it ideal for automotive applications.
Murata’s gyro sensor uses Coriolis force principle of detecting angular velocity, whereby four masses are positioned between two driving beams. By flexing the driving beams, the masses are vibrated along the x-axis. Then, when angular velocity is applied, two detecting masses are vibrated along the y-axis, producing a rotation in the opposite direction to the Coriolis force.
This technique results in lower acceleration noise, when compared to acceleration techniques, as the capacitive variations are cancelled out. Further, the device uses digital signal compensation to deliver low offset drift over the temperature range.