With the new BMA22 and BMA250 triaxial acceleration sensors, Bosch Sensortec is expanding its product portfolio to include small digital sensors in the LGA package with a footprint of 2 x 2 mm to become the market standard.

In fact the two new sensors, differing only with respect to accuracy of measurement, have exceptionally low power consumption: At full bandwidth and maximum data rate, they only need 100 µA of power, less than half as much as usual for components of this type, which is good for battery life.

The sensors are used in mobile consumer products such as cell phones, PDAs, game consoles, hard disks, notebooks, pedometers and electronic compasses in which they trigger position and motion controlled reactions. Bosch Sensortec already produces the BMA222 in large quantities; samples of the BMA250 are available.

With four programmable measuring ranges from ±2 g to ±16 g, the BMA222 offers designers a high degree of latitude for applications. An 8 bit data width ensures maximum resolution better than 16 milli-g.

The BMA250 model, which is pin and software compatible with the BMA222, even offers a resolution of as low as 4 milli-g at 10 bits. And the already low power requirement of both sensors can be significantly lowered even further by reducing the data rate, making it possible to achieve values of less than 5 µA.

Another ideal feature is the minimum allowable supply voltage, which at only 1.62 volts represents a new minimum value, just as the minimum allowable I/O voltage, which at only 1.2 volts, ensures that the sensors can communicate with state-of-the art microcontrollers.

Both of these acceleration sensors are equipped with programmable algorithms for internal motion analysis, which means they can automatically recognize specific motion patterns such as tapping on the device, falling (dropping) or lifting the device from its resting position. In movements of this type, the energy-consuming analysis using an external microcontroller can be eliminated. Recognized motion patterns are reported by the sensors with two independent interrupt outputs on the host application that can be programmed by the customer.