Bosch Sensortec BMA400 Ultra-low power, triaxial accelerometer GENERAL DESCRIPTION The BMA400 is the first real ultra-low power acceleration sensor without compromising on performance. Featuring 12-bit digital resolution, continuous measurement and a defined selectable bandwidth combined with ultra-low power the BMA400 allows low-noise measurement of accelerations in three perpendicular axes. The BMA400 thus senses tilt, orientation, tab/double tab, and enables plug 'n' play step counting with activity recognition especially suited for wearable devices, which need a long-lasting battery lifetime. Thanks to the continuous measurement principle and always-defined bandwidth, the BMA400 is the ideal solution for smart home applications such as smart indoor climate systems and smart home security systems. In the latter, the BMA400 can distinguish between real alarm situations like broken glass and false signals coming from random vibrations. Thereby, the new acceleration sensor avoids false alarms. even further, down to 800 nA. This mode offers an auto wake-up function to switch the sensor into any normal mode configuration when precise measurement is required. In addition, an auto ultra-low power feature is available to switch the sensor into its lowest current consumption configuration, when simple motion monitoring is needed. The BMA400 is highly configurable in terms of current consumption and noise performance in order to give the designer full flexibility when integrating the sensor into an always-on low power system. The integrated features enable the sensor to be used as main part of a power management unit. BMA400 Technical data Measurement range 2 g, 4 g, 8 g, 16 g Digital resolution 12 bit Output Data Rate (ODR) 12.5 Hz to 800 Hz Low path filter bandwidth Selectable 0.48xODR or 0.24xODR Current consumption (independent from ODR due to continuous measurement) Max. performance: 14 A Typical use case: < 8 A Low power use case: < 4 A Industrial applications (e.g. predictive maintenance, package tracking) Noise density Max. performance: < 220 g/Hz Typical use case: < 320 g/Hz Low power: < 600 g/Hz Power management of consumer end-devices based on motion Ultra low power / Auto-wake-up mode 800 nA @ 25 Hz ODR Embedded features - Step counter (< 4 A overall) - Activity recognition (walking, running, standing still) - Activity change - Orientation - Tab/Double tab (< 8 A overall) - General interrupt 1 and 2 (programmable via thresholds, timer, logical AND/OR operations) - 1 kB FIFO Offset 80 mg TCO 1 mg/K Interface SPI & IC & 2 Interrupt pins Supply voltage 1.71 V up to 3.6 V Package 12 pin LGA 2x2x0.95 m BMA400 TARGET APPLICATIONS IoT and smart home applications (e.g. indoor climate systems, security systems) Activity tracking and step counting in wearable devices (e.g. fitness bands, smart and regular watches, hearables) SENSOR FEATURES With its embedded features the BMA400 is unique in the class of ultra-low current accelerometers for wearable devices, smart home- and Internet of Things applications. The embedded step counter and activity recognition enables low current stepcounting and activity tracking at only 4 A overall current consumption. The plug'n' play step counter is optimized for wrist band usage and can also be used in other wearable devices. On top, the BMA400 integrates a multitude of other features (e.g. activity change, orientation, tab/double tab etc.) that facilitate its use especially in wearable devices and increase battery life significantly. Featuring continuous measurement and low pass filters in all power/noise configurations down to 3.2 A, the BMA400 is robust to vibrations and aliasing. In an additional ultra-low power mode the current consumption can be reduced Bosch Sensortec | BMA400 2|2 TECHNICAL SPECIFICATIONS Bottom view 2) Plug 'n' play embedded functionality: Acceleration data is computed already within the BMA400. The embedded features of the sensor can trigger an interrupt at certain selectable events which can be mapped to the selectable interrupt pins. In addition to the electrical interrupt, the status of the events and the counted steps are stored in the register map and can be read out easily. Embedded features: Pads visible! Step detector / Step counter Activity recognition: standing still, walking running Activity change (detects change of unspecific periodic activities) Orientation Tab/double tap General interrupt 1 und 2: programmable by threshold, timing, axes and logical AND/OR functionality. Pin configuration Pin Name Description 1 SDO Serial data output in SPI Address select in IC mode 2 SDX SDA serial data I/O in IC SDI serial data input in SPI 4W SDA serial data I/O in SPI 3W 3 VDDIO Digital I/O supply voltage (1.2 V ... 3.6 V) 4 NC Do not connect 5 INT1 Interrupt output 1 (default) 6 INT2 Interrupt output 2 (default) 7 VDD 8 GNDIO Power supply for analog & digital domain (1.62 V ... 3.6 V) Ground for I/O 9 GND Ground for digital & analog 10 CSB Chip select for SPI mode 11 NC Do not connect 12 SCX SCK for SPI serial clock SCL for IC serial clock SENSOR OPERATION 1) Standard data polling mode: Acceleration data is directly readout via the sensor's digital interface and computed by a system Controller or an application processor. Down to 3.2 A the acceleration data on the interface is always continuously measured and has a defined selectable bandwidth. An integrated FIFO with 1 kB of size as well as auto wake-up and auto ultra-low power can be used optionally to reduce the overall system current consumption. Feature parameters can be configured by the designer and thus perfectly support the adoption to the required use case and system design. SYSTEM COMPATIBILITY The BMA400 has been designed for best possible fit into modern wearable and IoT devices which are either nonchargeable or chargeable devices that require a long battery lifetime. Besides the lowest current consumption and superior performance, the BMA400 has very wide ranges for VDD and VDDIO supply voltages. The performance and the current consumption are stable over the whole voltage supply range. The BMA400 features I2C and SPI (3-wire/4-wire) digital, serial interfaces. The availability of data timestamping enables the synchronization of the acceleration data with other sensors connected to the same Controller or application processor. This reduces the complexity of sensor data fusion and additionally improves its precision. BMA400 is designed for plug `n' play functionality and ease-of-use in various system designs which require ultra-low current consumption on both sensor and system level. Headquarters Bosch Sensortec GmbH Gerhard-Kindler-Strasse 9 72770 Reutlingen * Germany Telephone +49 7121 3535 900 Fax +49 7121 3535 909 www.bosch-sensortec.com Data & Specification are preliminary and subject to change without notice | | Bosch Sensortec GmbH reserves all rights in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbols are registered trademarks of Robert Bosch GmbH, Germany. Doc.-Number: BST-BMA400-FL000-00 / Version_1.0_122017