The STMicroelectronics AIS2DW12 automotive accelerometer makes Passive Keyless Entry (PKE) radio fobs tough enough to survive the inevitable drops and scrapes in a lifetime of use. Also featuring ultra-low power consumption, the accelerometer adds practicality to the convenience and superior theft resistance that comes with motion awareness.
Ordinary PKE radio fobs listen continuously for an “unlock” request coming from the vehicle when it is touched. They then send a command to unlock the vehicle. Thieves can force a fob that is out of range – it could be placed on a table in the owner’s house -- to send an unlock command by relaying the request via an intermediate transmitter, and hence gain access and steal the vehicle.
Enhanced with an accelerometer, fobs can ignore malicious relayed transmissions by powering down the receiver when not moving and out of range. The radio wakes only when movement is detected at close range as the owner approaches the vehicle. In addition, deactivating the receiver during idle periods helps extend battery life.
Unlike some other accelerometers positioned for PKE, ST’s AIS2DW12 passes severe industry shock testing. Hence vehicle owners can enjoy greater security without taking extra care of a fragile fob, and with longer battery life as a bonus.
Leveraging the dedicated internal engine for efficient movement and orientation detection, the operating current of just 380 nA at 1.6 Hz is at least twice as good as alternative devices, further enhancing battery-energy savings. The AIS2DW12 operates from 1.8 V DC and can be powered from a single lithium cell, producing a digital output with full-scale range up to 4 g.
The AIS2DW12 is AEC-Q100 certified and compliant with automotive Product Part Approval Process (PPAP) Level-3. It is available now in a 2 mm × 2 mm × 1 mm 12-pad Land-Grid Array (LGA) package from $1.375 for orders of 1000 pieces.
