STMicroelectronics (NYSE: STM),
a leading developer of automotive semiconductors and MEMS (Micro Electro-Mechanical
System) technologies, has introduced a new motion sensor providing accurate
measurements of vehicle movement for systems such as adaptive front lights,
auto-levelling HID (high-intensity discharge) lamps, inertial brake lights,
e-parking brake, advanced anti-theft systems and control of vehicle dynamics.
The AIS226DS is a two-axis in-plane accelerometer capable of greater accuracy
than is possible using two individual sensors. The device senses acceleration
up to ±6g, where one ‘g’ is the acceleration due to gravity.
As an example, 3g is the approximate acceleration experienced in a manned rocket
during launch into space. The new AIS226DS can also resolve incredibly tiny
angles of incline, smaller than 0.02 degrees. The ability to accurately measure
incline is important in auto-leveling lamp, e-parking brake, and HSA (Hill Start
Motion is sensed using a tiny MEMS motion detector built on a silicon chip.
An interface chip, available with an SPI or I2C output, is also integrated,
enabling direct connection to the vehicle’s Electronic Control Unit (ECU).
Other vehicle systems that can use the AIS226DS include event recorders for
monitoring accidents or abusive driving, and GPS navigation systems using movement
data for improved dead reckoning when the satellite signal is lost. There are
also many non-automotive applications, such as vibration sensing in industrial
equipment, black-box security monitors for shipping containers, inclinometers,
and robotic systems.
The AIS226DS owes part of its high sensing accuracy to the low intrinsic noise
of the electronic interface chip, which includes high-precision 16-bit analog-to-digital
converters. The low noise allows usable converter resolution of 14 bits over
a significant bandwidth, corresponding to a resolution of 0.25mg (on 2g full-scale).
The sensor is also highly stable and maintains high accuracy (±70mg)
throughout the automotive temperature range –40 to +105 degrees C, offering
offset drift in the range of 0.2mg per degree C. The AIS226DS, assembled in
a sturdy SO16W full-molded package, is qualified to the AEC-Q100 automotive
The AIS226DS is sampling to lead customers, with volume production planned
for Q1 2010. Pricing is from $2.50 in quantities of 100,000 units.