SensorDynamics launches fail-safe gyroscope for the automotive field

SensorDynamics, a producer of sensors for the automotive and manufacturing industries, today announced the launch of the micromechanical SD721 and SD751 gyroscopes (angular rate sensors), a solution that integrates monitoring circuitry at chip and module level to make it absolutely fail-safe. Compactness, mechanical ruggedness and high stability in the long term make it especially suitable for automotive applications such as in electronic stabilizing systems (vehicle dynamics control), for turnover detection or in navigational systems for driving blind without GPS support. The first generation has already earned the AEC-Q100 certification and seriestested devices of the second generation are available now.

FAIL-SAFE AND FURTHER FEATURES

The SD721’s and SD751’s monitoring circuitry that encompasses both the sensor element and all analogue digital blocks is in response to high safety standards, especially in the automobile sector. This circuitry alerts immediately if a parameter goes out of precisely defined limits. More than 40 parameters are monitored to ensure that it is completely fail-safe. All design measures involved in achieving this are to IEC 61508 standard. Failure of the gyroscope is communicated to the superordinate microcontroller on an SPI interface plus a hard-wired line. The sensor is also able to monitor the microcontroller by means of a handshake. If the latter should fail, the sensor may cut out the entire module. On the strength of this design, the micromechanical gyroscope achieves SIL 2 at component level and SIL 3 at system level.

“Precise FMEA, multiple levels of circuit supervision and redundant transfer of a fault message have enabled us to create fail-safe sensors for a very wide market,” said Hubertus Christ, CEO of SensorDynamics.

An operating temperature range of up to 125°C makes the SD721 and SD751 extremely flexible in terms of placement. It can be installed in the passenger compartment of a vehicle or under the bonnet. It also exhibits extremely low crosssensitivity to rotation on other axes and acceleration. Other features include a small offset error and extremely fast recovery after impact. This is only 5 milliseconds after a 50 g shock, with 1 g being the equivalent of gravitational acceleration.

SPECIFICATIONS OF THE SD721 AND SD751 AT A GLANCE

The SD721 and SD751 can be used to implement measurement ranges from +/-10 to +/-500 °/s. The following data

applies to a range of +/-100 °/s:

:: Resolution 0.0039 °/s/LSB

:: Signal/noise (BW = 25 Hz) 0.1 °/s

:: Sensitivity error +/-2%

:: Linearity error +/-0.2% FS

:: Offset error at 25°C +/-0.5 °/s

:: Cross-sensitivity to rotation about other axes 2%

:: Cross-sensitivity to acceleration 0.1 °/s/g

:: SPI interface

:: Impact resistance in operation +/-1,500 g

:: Recovery time of 5 ms after 50 g impact

:: Operating temperature range -40 to +125°C

:: SD721 – SOIC28 package

:: SD751 – OC24 package

VARIETY OF APPLICATIONS

Gyroscopes measure the speed of rotation of a body. They can therefore be used to reliably identify common and dangerous situations such as skidding or overturning vehicles – classic uses in the automotive field. For instance, a special-purpose sensor of this kind can help to compensate skidding movements as part of an electronic stabilizing or dynamics control system. It will also recognize that a vehicle is overturning and trigger a head airbag. If GPS guidance fails, it can also detect the driving direction and support a vehicle’s navigation system by calculating its position from the direction and speed.

The SD721 and SD751 can also be recommended for stabilizing platforms in safety-relevant industrial applications.

Likewise conceivable is its use in high-grade consumer applications such as camcorders or game consoles to detect tipping motion.

FABRICATION

The second-generation sensor element is being manufactured at the automotive-certified SensorDynamics site for MEMS sensors in Itzehoe in Northern Germany. The ASIC that forms part of the SD721 and SD751 comes from the semiconductor fab of ST Microelectronics.

The two components are SOIC28 or OC24 packaged and tested by ASE in Korea. SensorDynamics’ own quality and logistics specialists are responsible for the entire manufacturing process.

AVAILABILITY AND PRICE

The SD721 and SD751 is now available. Pricing is about 35 US$ per consignment of 1,000. The SD721 and SD751 will be presented for the first time at AutoTronics show in Taipei/Taiwan from 9 to 12 April and at the Sensor + Test show in Nuremberg from 6 to 8 May, 2008.

ABOUT SENSORDYNAMICS

SensorDynamics is a fast-growing semi-fabless semiconductor company that focuses on innovative sensor solutions for high volume applications in automotive and industry. SensorDynamics develops and supplies fail-safe micro and wireless semiconductor sensor systems for automotive key accounts mainly and is certified under TS16949. The company acts as general contractor with in-house MEMS production and cooperates closely with world-leading suppliers of manufacturing and testing technologies.

Headquartered in Graz-Lebring, Austria, SensorDynamics has subsidiaries in Italy, Germany, Slovenia and France. For more information on SensorDynamics, its products and services, please go to