Description

The AIS1200PS is a peripheral acceleration sensor with a single-axis sensing element and an IC interface able to provide acceleration information to a master control unit through a Manchester-coded protocol (125 kbps). The sensing element, capable of detecting the acceleration, is manufactured using a dedicated process developed by ST to produce inertial sensors and actuators in silicon.
The IC interface is manufactured using a BCD process that allows a high level of integration. The device is factory trimmed to better tune the sensing element characteristics with the acceleration information to be supplied.
The AIS1200PS has a full scale of ±200 g. The acquisition chain is made up of a C/V converter, a full-differential charge amplifier, a 2nd order LPF with a cutoff frequency of 175 Hz, and a second charge amplifier to adapt the dynamic range to an SAR A/D converter.
The differential capacitance of the sensor is proportional to the proof mass displacement; thus, by sensing the differential capacitance, the position of the sensor is determined. Then, since the mass position is known and the position is related to the input acceleration, the input acceleration can be easily deduced.
The device is available in a plastic SOIC package with 150 mils reverse frame forming for EMC enhancement and is specified over a temperature range extending from -40 °C to +125 °C.