SMB365

The SMB365 is a triaxial low-g acceleration sensor for consumer market applications. It allows measurements of static as well as dynamic accelerations. Due to its three perpendicular axes it gives the absolute orientation in a gravity field. As all other Bosch inertial sensors, it is a twochip arrangement. An application-specific IC evaluates the output of a three-channel micromechanical acceleration-sensing element that works according to the differential capacitance principle. The underlying micromachining process has proven its capability in more than 100 million Bosch accelerometers and gyroscopes so far.

The SMB365 provides a digital 10bit output signal via an SPI interface. With an appropriate SPI command the full measurement range can be chosen to 2g or 10g. A first-order filter with a pole-frequency of 50Hz is included to provide preconditioning of the measured acceleration signal. Typical noise level and quantization lead to a sensitivity resolution of 4mg or an accuracy of 0.3° in an inclination sensing application, respectively. The current consumption is typically 600A at a supply voltage of 2.5V. Furthermore, the sensor can be switched into a low-power mode where it informs the host system about an acceleration change via an interrupt pin. This feature can be used to wake-up the host system from a sleep mode.

The sensor SMB365 also features full self-test capability. It is activated via SPI command which results in a physical deflection of the seismic mass in the sensing element due to an electrostatic force. Thus, it provides full testing of the complete signal evaluation path including the micromachined sensor structure and the evaluation ASIC.

The sensor SMB365 is available in a standard SMD QFN package with a footprint of 4x4mm² and a height of 1.2mm.