A Low-g 3 Axis Accelerometer for Emerging Automotive Applications
A 30 µg/sqrt(Hz) resolution MEMS based low-g 3-axis accelerometers targeted for emerging automotive application is presented. The device is composed by 2-dice in a single package: the sensing element and the processing IC. The sensing element is realized
- PDF / 767,615 Bytes
- 12 Pages / 439.37 x 666.142 pts Page_size
- 82 Downloads / 190 Views
A Low-g 3 Axis Accelerometer for Emerging Automotive Applications
B. Grieco, D. Ausilio, F. Banfi, E. Chiesa, G. Frezza, E. Lasalandra, P. Galletta, M. Garavaglia, A. Mancaniello, A. Merassi, F. Pasolini, G. Sironi, F. Speroni, M. Tronconi, T. Ungaretti, B. Vigna, S. Zerbini, ST Microelectronics Abstract A 30 µg/sqrt(Hz) resolution MEMS based low-g 3-axis accelerometers targeted for emerging automotive application is presented. The device is composed by 2-dice in a single package: the sensing element and the processing IC. The sensing element is realized with an epitaxial micro-machining process (ThELMA™) while the IC uses a 0.5 µm BICMOS process. The IC amplifier is able to detect capacitive changes as low as 10 aF (10·10-18 F) and the device is able to provide both an analog and a digital output. Moreover it has very good linearity and very low cross talk between the sensing axes thanks to a design that fits very well the ST micro-machining process ThELMA. Finally, the proposed interface accelerometer is factory-trimmed to ensure repeatable performance without production-line adjustments in the end product The device is intended for new inertial applications in the automotive field that are expected to be heavily dominated by micromachined silicon components More specifically multiaxis accelerometers are particularly useful for emerging application like new generation ESP and ABS system, assisted navigation, headlight leveling, car alarm and virtual horizon.
1
Introduction
LIS3L02 is the first 3 axis low-g linear accelerometer on the market able to measure 30 millionths (micro) of gravity acceleration with the lowest power consumption at 2.7 Volt supply integrated in a single package. The output data are available in analog and digital format. The device is also very robust against mechanical shock being compliant with drop test requirements.
212
Safety
LIS3L02 is a dual silicon chip solution inside a single package (PSO24: 15.3 mm x 7 mm x 2.5 mm or QFPN44: 7 mm x 7 mm x 1.8 mm): the sensor chip and the interface electronics. This approach allows the maximum flexibility, genericity and modularity together with a shorter development time for new products. Most advanced solution currently available on the market can provide only: Maximum of 2-axis sensing feature integrated with the electronics in a single package. 3 axis sensing element without the interface electronics. Bulky solutions at PCB level realized by assembling 1 or 2 axis accelerometers. Among all the competing 3 axis accelerometers only ST 3-axis accelerometer is able to provide outstanding performances in a small package with low power consumption. The achievement of this breakthrough in the field of micro-machined accelerometers has been possible thanks to different innovations, which allowed overcoming the following technical challenges: Achievement of an excellent process control in the manufacturing of an in-plane (XY) and out-of-plane (Z) sensitive micro-mechanical structure on the same die. The challenge was to optimize and control bot
Data Loading...
