Mobility Solutions

New Bosch MEMS acceleration sensors Fifth generation of sensitive crash detectors SMA58x and SMA59x in SOIC14n housing

  • Total of four measurement ranges, from ±120 g to ±480 g
  • Programmable via SPI or PSI5 interface
  • PSI5 interface with optimized bus performance
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  • September 25, 2012
  • Mobility Solutions
  • Press releases
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press release

Bosch has introduced the next generation of peripheral acceleration sensors for passenger protection systems in vehicles – the fifth since 1996. The key features of the new digital sensors include a wide measurement range of between ±120 g and ±480 g and the choice of communication via the SPI or the PSI5-V1.3 interface. Peripheral sensors are located at the outermost points of a vehicle's engine compartment, at the sides, or at the rear, thus enabling them to recognize a collision quickly. However, the new fifth-generation models can do more than simply register a crash. In just a few milliseconds, they transfer to the airbag control unit all the data needed by the electronics system to determine with absolute certainty whether a collision is minor or serious. The control unit checks the plausibility of the incoming sensor data before deciding which vehicle restraint systems (e.g. front, head or side airbag and seat-belt pretensioners) to activate.

Four measurement ranges, two sensors, straightforward integration
Apart from their measurement ranges, the two new sensors are of virtually identical design. The SMA58x can be switched from ±120 g to ±240 g and is designed to be integrated into the peripheral side collision sensors. The SMA59x, with twice the measurement range, is specially designed for front collisions. Both sensors measure along the Y axis. The 10-bit measured-value resolution and measurement range limit values are used to calculate sensitivity values of between 1 LSB/g and 4 LSB/g.

Thanks to the PSI5-V.1.3 bus interface, the sensors can be easily integrated, provided the airbag control unit also features a Peripheral Sensor Interface 5. Up to four bus users can then be operated in parallel or in series. To ensure the databus continues to function smoothly under such conditions, the new acceleration sensors feature an IDATA pin, which is used to select filters or attenuators with customer-specific dimensions. This wiring is integrated into the housing of the peripheral sensors along with the sensor chip.

Bosch engineers have equipped the SMA58x and the SMA59x with an ultra effective offset controller. This automatically makes both slow and fast offset adjustments. As a result, the sensors are very resilient to physical disturbances such as vibrations or significant fluctuations in ambient temperature. Two selectable low-pass filters with cut-off frequencies of 213 Hz and 416 Hz are also used to enhance signal conditioning.

Background information on MEMS technology
Bosch has shaped the development of MEMS technology (micro-electro-mechanical systems) from the outset. The company has manufactured well over two billion MEMS sensors since production began in 1993. Production volumes reach new highs year after year. In 2011 alone, around half a billion sensors rolled off the production lines in Reutlingen, making Bosch the global market leader. Its product portfolio comprises pressure sensors, acceleration sensors, yaw-rate sensors, and inertial sensors as well as MEMS microphones and terrestrial magnetic field sensors for a variety of automotive and consumer electronics applications. More information on Bosch vehicle sensors is available at www.bosch-sensors.com.

 Technical data – SMA58x/SMA59x (extract - typical values)
 Measurement ranges SMA58x: ±120 g und ±240 g
 SMA59x: ±240 g und ±480 g
 Sensierachse Y
 Measured-value resolution 10 bits
 Linearity deviation ±2 %
 Permissible ambient temperature -40 °C to +125 °C
 Supply voltage Max. 11 V
 Current drain Max. 8 mA
 Housing SOIC14n § 8.6 mm x 3.9 mm
 Certificates Environment: RoHS
 Delivery capability Series production under way, sample on request


Readers' contact:
Jochen Volm (AE/SCS2)
Phone +49 7121 35-6651

Mobility Solutions is the largest Bosch Group business sector. In 2015, its sales came to 41.7 billion euros, or 59 percent of total group sales. This makes the Bosch Group one of the leading automotive suppliers. The Mobility Solutions business sector combines the group’s expertise in three mobility domains – automation, electrification, and connectivity – and offers its customers integrated mobility solutions. Its main areas of activity are injection technology and powertrain peripherals for internal-combustion engines, diverse solutions for powertrain electrification, vehicle safety systems, driver-assistance and automated functions, technology for user-friendly infotainment as well as vehicle-to-vehicle and vehicle-to-infrastructure communication, repair-shop concepts, and technology and services for the automotive aftermarket. Bosch is synonymous with important automotive innovations, such as electronic engine management, the ESP anti-skid system, and common-rail diesel technology.

The Bosch Group is a leading global supplier of technology and services. It employs roughly 375,000 associates worldwide (as of December 31, 2015). The company generated sales of 70.6 billion euros in 2015. Its operations are divided into four business sectors: Mobility Solutions, Industrial Technology, Consumer Goods, and Energy and Building Technology. The Bosch Group comprises Robert Bosch GmbH and its roughly 440 subsidiaries and regional companies in some 60 countries. Including sales and service partners, Bosch’s global manufacturing and sales network covers some 150 countries. The basis for the company’s future growth is its innovative strength. Bosch employs 55,800 associates in research and development at 118 locations across the globe. The Bosch Group’s strategic objective is to deliver innovations for a connected life. Bosch improves quality of life worldwide with products and services that are innovative and spark enthusiasm. In short, Bosch creates technology that is “Invented for life.”

Further information is available online at www.bosch.com and www.bosch-press.com, http://twitter.com/BoschPresse.

PI7724 - September 25, 2012

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