LIS3L02AS4 INERTIAL SENSOR: 3Axis - 2g/6g LINEAR ACCELEROMETER PRODUCT PREVIEW ■ 2.4V TO 5.25V SINGLE SUPPLY OPERATION ■ THE SENSITIVITY IS ADJUSTED WITH A TOTAL ACCURACY OF ±10% ■ THE OUTPUT VOLTAGE, OFFSET, SENSITIVITY AND TEST VOLTAGE ARE RATIOMETRIC TO THE SUPPLY VOLTAGE SO-24 ORDERING NUMBER: LIS3L02AS4 ■ DEVICE SENSITIVITY IS ON-CHIP FACTORY TRIMMED ■ EMBEDDED SELF TEST ■ HIGH SHOCK SURVIVABILITY over a maximum bandwidth of 4.0 KHz for the X and Y axis and 2.5 KHz for the Z axis. The device band- DESCRIPTION width may be reduced by using external capacitanc- es. A self-test capability allows the user to check the The LIS3L02AS4 is a tri-axis linear accelerometer functioning of the system. that includes a sensing element and an IC interface able to take the information from the sensing element The LIS3L02AS4 is available in plastic SMD package and to provide an analog signal to the external world. and it is specified over a temperature range extend- ing from -40°C to +85°C. The sensing element, capable to detect the acceler- ation, is manufactured using a dedicated process The LIS3L02AS4 belongs to a family of products suit- called THELMA (Thick Epi-Poly Layer for Microactu- able for a variety of applications: ators and Accelerometers) developed by ST to pro- – Antitheft systems duce inertial sensors and actuators in silicon. – Inertial navigation The IC interface instead is manufactured using a – Virtual reality input devices CMOS process that allows high level of integration to design a dedicated circuit which is trimmed to better – Vibration Monitoring, recording and compen- match the sensing element characteristics. sation The LIS3L02AS4 has a user selectable full scale of – Appliance control 2g, 6g and it is capable of measuring accelerations – Robotics BLOCK DIAGRAM Routx S1X Voutx CHARGE S/H S1Y AMPLIFIER S1Z rot Routy Vouty MUX DEMUX S/H S2Z S2Y Routz S2X Voutz S/H CLOCK TRIMMING CIRCUIT VOLTAGE & CURRENT & & REFERENCE TEST INTERFACE PHASE GENERATOR February 2004 1/8 This is preliminary information on a new product now in development. Details are subject to change without notice. LIS3L02AS4 PIN DESCRIPTION N° Pin Function 1 to 5 NC Internally not connected 6 GND 0V supply 7 Vdd Power supply 8 Vouty Output Voltage 9 ST Self Test (Logic 0: normal mode; Logic 1: Self-test) 10 Voutx Output Voltage 11 PD Power Down (Logic 0: normal mode; Logic 1: Power-Down mode) 12 Voutz Output Voltage 13 FS Full Scale selection (Logic 0: 2g Full-scale; Logic 1: 6g Full-scale) 14-15 Reserved Leave unconnected or connect to Vdd 16 Reserved Connect to Vdd or ground 17 Reserved Leave unconnected or connect to Vdd 18 Reserved Leave unconnected or connect to ground 19 to 24 NC Internally not connected PIN CONNECTION (Top view) NC NC NC NC DIRECTION OF THE NC NC DETECTABLE ACCELERATIONS NC NC Y 1 NC NC GND NC Vdd Reserved Vouty Reserved 13 Z X ST Reserved Voutx Reserved PD Reserved Voutz FS 2/8 LIS3L02AS4 ELECTRICAL CHARACTERISTiCS (Temperature range -40°C to +85°C) All the parameters are specified @ Vdd=3.3V and T=25°C unless otherwise noted 1 Symbol Parameter Test Condition Min. Max. Unit Typ. Vdd Supply voltage 2.4 5.25 V Idd Supply current 850 µA Voff Zero-g level T = 25°C Vdd/2-18% Vdd/2 Vdd/2+18% V 2 Ar T = 25°C ±1.8 ±2.0 ±2.2 g Acceleration range FS pin connected to GND T = 25°C ±6.0 g FS pin connected to Vdd So Sensitivity ratiometric to Vdd T = 25°C Vdd/5–10% Vdd/5 Vdd/5+10% V/g Full-scale = 2g T = 25°C Vdd/15–10% Vdd/15 Vdd/15+10% V/g Full-scale = 6g NL Non Linearity Best fit straight line ±1 % FS X, Y axis Full-scale = 2g Best fit straight line ±3% FS Z axis Full-scale = 2g fuc Sensing Element Resonant X, Y axis 4.0 KHz Frequency Z axis 2.5 KHz an Acceleration noise density Vdd=5V 50 µg/ Hz Full-scale = 2g Vt Self test output voltage T = 25°C 33 mV Vdd=3.3V T = 25°C 115 mV Vdd=5V Vst Self test input Logic 0 level 0 0.8 V Logic 1 level 2.2 Vdd V Rout Output impedance 100 kΩ 3 Cload 320 pF Capacitive load drive Notes: 1. Typical specifications are not guaranteed 2. Guaranteed by wafer level test and measurement of initial offset and sensitivity 3. Bandwidth=1/(2*π*100KΩ*Cload) 3/8 LIS3L02AS4 ABSOLUTE MAXIMUM RATING Stresses above those listed as “absolute maximum ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device under these conditions is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. Symbol Ratings Maximum Value Unit Vdd Supply voltage -0.3 to 6 V Vin Input voltage on any control pin (FS, PD, ST) Vss -0.3 to Vdd +0.3 V A Acceleration (Any axis, Powered, Vdd=3.3V) 3000g for 0.5 ms POW A Acceleration (Any axis, Unpowered) 3000g for 0.5 ms UNP T Operating Temperature Range -40 to +85 °C OP T Storage Temperature Range -40 to +105 °C STG 1 FUNCTIONALITY The LIS3L02AS4 is a low-cost, analog output three-axis linear accelerometer packaged in SO24 package. The complete device includes a sensing element and an IC interface able to take the information from the sensing element and to provide an analog signal to the external world. 1.1 Sensing element The THELMA process is utilized to create a surface micro-machined accelerometer. The technology allows to carry out suspended silicon structures which are attached to the substrate in a few points called anchors and free to move on a plane parallel to the substrate itself. To be compatible with the traditional packaging tech- niques a cap is placed on top of the sensing element to avoid blocking the moving parts during the molding phase. The equivalent circuit for the sensing element is shown in the below figure; when a linear acceleration is applied, the proof mass displaces from its nominal position, causing an imbalance in the capacitive half-bridge. This im- balance is measured using charge integration in response to a voltage pulse applied to the sense capacitor. The nominal value of the capacitors, at steady state, is few pF and when an acceleration is applied the maximum variation of the capacitive load is few tenth of pF. 4/8 LIS3L02AS4 Figure 1. Equivalent electrical circuit C R ps1 s1 S1x C s1x C R pr r C s2x S2x C R ps2 s2 C R ps1 s1 S1y C s1y C R pr r rot C s2y S2y C R ps2 s2 C R ps1 s1 S1z C s1z C R pr r C s2z S2z C R ps2 s2 1.2 IC Interface The complete signal processing uses a fully differential structure, while the final stage converts the differential signal into a single-ended one to be compatible with the external world. The first stage is a low-noise capacitive amplifier that implements a Correlated Double Sampling (CDS) at its output to cancel the offset and the 1/f noise. The produced signal is then sent to three different S&Hs, one for each channel, and made available to the outside. The low noise input amplifier operates at 200 kHz while the three S&Hs operate at a sampling frequency of 66 kHz. This allows a large oversampling ratio, which leads to in-band noise reduction and to an accurate output waveform. All the analog parameters (output offset voltage and sensitivity) are ratiometric to the voltage supply. Increasing 5/8 LIS3L02AS4 or decreasing the voltage supply, the sensitivity and the offset will increase or decrease linearly. The feature provides the cancellation of the error related to the voltage supply along an analog to digital conversion chain. 1.3 Factory calibration The IC interface is factory calibrated to provide to the final user a device ready to operate. The parameters which are trimmed are: gain, offset, common mode and internal clock frequency. The trimming values are stored inside the device by a non volatile structure. Any time the device is turned on, the trimming parameters are downloaded into the registers to be employed during the normal operation thus allowing the final user to employ the device without any need for further calibration. 6/8 LIS3L02AS4 mm inch OUTLINE AND DIM. MECHANICAL DATA MIN. TYP. MAX. MIN. TYP. MAX. A 2.35 2.65 0.093 0.104 A1 0.10 0.30 0.004 0.012 A2 2.55 0.100 B 0.33 0.51 0.013 0.0200 C 0.23 0.32 0.009 0.013 D 15.20 15.60 0.598 0.614 E 7.40 7.60 0.291 0.299 e 1.27 0,050 H 10.0 10.65 0.394 0.419 h 0.25 0.75 0.010 0.030 k0˚ (min.), 8˚ (max.) SO24 L 0.40 1.27 0.016 0.050 h x 45˚ A1 K Be A1 C 0.10mm L .004 H Seating Plane D 24 13 1 12 SO24 7/8 A2 E A LIS3L02AS4 Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners © 2004 STMicroelectronics - All rights reserved STMicroelectronics GROUP OF COMPANIES Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States www.st.com 8/8