LIS3L02AS5 MEMS INERTIAL SENSOR: 3-axis - ±2g/6g LINEAR ACCELEROMETER Features ■ 4.5 TO 5.5V SINGLE SUPPLY OPERATION ■ LOW POWER CONSUMPTION ■ ±2g/±6g USER SELECTABLE FULL-SCALE ■ 0.5mg RESOLUTION OVER 100Hz BANDWIDTH ■ EMBEDDED SELF TEST AND POWER DOWN ■ OUTPUT VOLTAGE, OFFSET AND SENSITIVITY RATIOMETRIC TO THE SUPPLY VOLTAGE ■ HIGH SHOCK SURVIVABILITY ■ LEAD FREE AND ECOPACK COMPATIBLE Description The LIS3L02AS5 is a low-power three axes linear accelerometer that 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. 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 standard CMOS process that allows high level of integration SO24 to design a dedicated circuit which is trimmed to better match the sensing element characteristics. The LIS3L02AS5 has a user selectable full scale of ±2g, ±6g and it is capable of measuring accelerations over a bandwidth of 1.5kHz for all axes. The device bandwidth may be reduced by using external capacitances. A self-test capability allows to check the mechanical and electrical signal path of the sensor. The LIS3L02AS5 is available in plastic SMD package and it is specified over an extended temperature range of -40°C to +85°C. The LIS3L02AS5 belongs to a family of products suitable for a variety of applications: – Mobile terminals – Gaming and Virtual Reality input devices – Free-fall detection for data protection – Antitheft systems and Inertial Navigation – Appliance and Robotics. Order codes Part number Temp range, ° C Package Packing LIS3L02AS5 -40°C to +85°C SO24 Tray LIS3L02AS5TR -40°C to +85°C SO24 Tape & Reel December 2005 Rev 1 1/14 www.st.com 14 LIS3L02AS5 Contents 1 2 3 4 Block Diagram & Pins Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Mechanical and Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 Mechanical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.4 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.1 Sensing element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.2 IC Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.3 Factory calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Application hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.1 Soldering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.2 Output response vs orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 5 Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2/14 LIS3L02AS5 1 Block Diagram & Pins Description 1 Block Diagram & Pins Description 1.1 Block diagram Figure 1. Block Diagram X+ CHARGE AMPLIFIER Y+ Z+ a MUX Routx Voutx Routy Vouty Routz Voutz S/H DEMUX ZY- S/H XS/H REFERENCE SELF TEST 1.2 TRIMMING CIRCUIT CLOCK Pin Description Figure 2. Pin Connection (top view) DIRECTION OF THE DETECTABLE ACCELERATIONS X 13 Y 1 Z NC NC NC NC NC NC NC NC NC NC GND NC Vdd Reserved Vouty Reserved ST Reserved Voutx Reserved PD Reserved Voutz FS 3/14 LIS3L02AS5 1 Block Diagram & Pins Description Table 1. 4/14 Pin description Pin # Pin Name Function 1 to 5 NC 6 GND 0V supply 7 Vdd Power supply 8 Vouty 9 ST 10 Voutx 11 PD 12 Voutz 13 FS 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 Output Voltage Self Test (Logic 0: normal mode; Logic 1: Self-test) Output Voltage Power Down (Logic 0: normal mode; Logic 1: Power-Down mode) Output Voltage Full Scale selection (Logic 0: 2g Full-scale; Logic 1: 6g Full-scale) Internally not connected LIS3L02AS5 2 Mechanical and Electrical Specifications 2 Mechanical and Electrical Specifications 2.1 Mechanical Characteristics. Table 2. Symbol Ar So Mechanical Characteristics1 (Temperature range -40°C to +85°C) All the parameters specified @ Vdd = 5.0V, T = 25°C unless otherwise noted Parameter Acceleration Range3 Sensitivity4 Min. Typ.2 FS pin connected to GND ±1.8 ±2.0 g FS pin connected to Vdd ±5.4 ±6.0 g Full-scale = 2g Vdd/5–10% Vdd/5 Vdd/5+10% V/g Full-scale = 6g Vdd/15–10% Vdd/15 Vdd/15+10% V/g Test Condition Max. Unit SoDr Sensitivity Change Vs Temperature Delta from +25°C Voff Zero-g Level4 T = 25°C Zero-g level Change Vs Temperature Delta from +25°C ±1.1 Best fit straight line Full-scale = 2g X, Y axis ±0.3 ±1.5 % FS Best fit straight line; Full-scale = 2g Z axis ±0.6 ±2 % FS ±2 ±4 % OffDr NL Non Linearity5 ±0.01 Vdd/2-10% CrossAx Cross-Axis6 An Vt Fres Acceleration Noise Density Self test Output Voltage Change7,8,9 Vdd=5.0V; Full-scale = 2g Vdd/2 %/°C Vdd/2+10% V mg/°C µg/ Hz 50 T = 25°C Vdd=5.0V Full-scale = 2g X axis -70 -160 -320 mV T = 25°C Vdd=5.0V Full-scale = 2g Y axis 70 160 320 mV T = 25°C Vdd=5.0V Full-scale = 2g Z axis -70 -130 -320 mV Sensing Element all axes Resonance Frequency10 1.5 KHz 5/14 LIS3L02AS5 2 Mechanical and Electrical Specifications Mechanical Characteristics1 (continued) (Temperature range -40°C to +85°C) All the parameters specified @ Vdd = 5.0V, T = 25°C unless otherwise noted Table 2. Symbol Parameter Top Operating Temperature Range Wh Product Weight Test Condition Typ.2 Min. -40 Max. Unit +85 °C 0.6 gram Note: 1 The product is factory calibrated at 5.0V. The device can be powered from 4.5V to 5.5V. Voff, So and Vt parameters will vary with supply voltage. 2 Typical specifications are not guaranteed 3 Verified by wafer level test and measurement of initial offset and sensitivity 4 Zero-g level and sensitivity are essentially ratiometric to supply voltage 5 Guaranteed by design 6 Contribution to the measuring output of an inclination/acceleration along any perpendicular axis 7 “Self test output voltage change” is defined as Vout(Vst=Logic1)-Vout(Vst=Logic0) 8 “Self test output voltage change” varies cubically with supply voltage 9 When full-scale is set to ±6g, “self-test output voltage change” is one third of the specified value. 10 Minimum resonance frequency Fres=1.5KHz. Sensor bandwidth=1/(2*π*110KΩ*Cload) with Cload>1nF. 2.2 Electrical Characteristics Table 3. Symbol Electrical Characteristics1 (Temperature range -40°C to +85°C) All the parameters are specified @ Vdd =5.0V, T=25°C unless otherwise noted Parameter Test Condition Min. Typ.2 Max. Unit 4.5 5 5.5 V Vdd Supply Voltage Idd Supply Current mean value PD pin connected to GND 1.0 1.5 mA Supply Current in Power Down Mode rms value PD pin connected to Vdd 2.5 5 µA IddPdn Vst Logic 0 level 0 0.8 V Logic 1 level 3.6 Vdd V 140 kΩ Self Test Input Rout Output Impedance 80 Cload Capacitive Load Drive3 320 Ton Turn-On Time at exit from Cload in µF Power Down mode 110 pF 550*Cload+0.3 ms Note: 1 The product is factory calibrated at 5.0V 2 Typical specifications are not guaranteed 3 Minimum resonance frequency Fres=1.5KHz. Sensor bandwidth=1/(2*π*110kΩ*Cload) with Cload>1nF 6/14 LIS3L02AS5 2.3 2 Mechanical and Electrical Specifications Absolute maximum ratings 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. Table 4. Absolute maximum ratings Symbol Ratings Vdd Supply voltage Vin Input Voltage on Any Control pin (FS, PD, ST) Unit -0.3 to 7 V -0.3 to Vdd +0.3 V 3000g for 0.5 ms APOW Acceleration (Any axis, Powered, Vdd=5.0V) AUNP Acceleration (Any axis, Not powered) TSTG Storage Temperature Range ESD Maximum Value 10000g for 0.1 ms 3000g for 0.5 ms 10000g for 0.1 ms Electrostatic Discharge Protection -40 to +125 °C 2 (HBM) kV 200 (MM) V 1500 (CDM) V This is a Mechanical Shock sensitive device, improper handling can cause permanent damages to the part This is an ESD sensitive device, improper handling can cause permanent damages to the part 2.4 Terminology Sensitivity describes the gain of the sensor and can be determined by applying 1g acceleration to it. As the sensor can measure DC accelerations this can be done easily by pointing the axis of interest towards the center of the earth, note the output value, rotate the sensor by 180 degrees (point to the sky) and note the output value again thus applying ±1g acceleration to the sensor. Subtracting the larger output value from the smaller one and dividing the result by 2 will give the actual sensitivity of the sensor. This value changes very little over temperature (see sensitivity change vs. temperature) and also very little over time. The Sensitivity Tolerance describes the range of Sensitivities of a large population of sensors. Zero-g level describes the actual output signal if there is no acceleration present. A sensor in a steady state on an horizontal surface will measure 0g in X axis and 0g in Y axis whereas the Z axis will measure +1g. The output is ideally for a 5.0V powered sensor Vdd/2 = 2500mV. A deviation from ideal 0-g level (2500mV in this case) is called Zero-g offset. Offset of precise MEMS sensors is to some extend a result of stress to the sensor and therefore the offset can slightly change after mounting the sensor onto a printed circuit board or exposing it to extensive mechanical stress. Offset changes little over temperature - see “Zero-g Level Change vs. Temperature”- the Zero-g level of an individual sensor is very stable over lifetime. The Zero-g level tolerance describes the range of zero-g levels of a population of sensors. 7/14 2 Mechanical and Electrical Specifications LIS3L02AS5 Self Test allows to test the mechanical and electric part of the sensor, allowing the seismic mass to be moved by means of an electrostatic test-force. The Self Test function is off when the ST pin is connected to GND. When the ST pin is tied at Vdd an actuation force is applied to the sensor, simulating a definite input acceleration. In this case the sensor outputs will exhibit a voltage change in their DC levels which is related to the selected full scale and depending on the Supply Voltage through the device sensitivity. When ST is activated, the device output level is given by the algebraic sum of the signals produced by the acceleration acting on the sensor and by the electrostatic test-force. If the output signals change within the amplitude specified inside Table 2, than the sensor is working properly and the parameters of the interface chip are within the defined specification Output impedance describes the resistor inside the output stage of each channel. This resistor is part of a filter consisting of an external capacitor of at least 320pF and the internal resistor. Due to the high resistor level only small, inexpensive external capacitors are needed to generate low corner frequencies. When interfacing with an ADC it is important to use high input impedance input circuitries to avoid measurement errors. Note that the minimum load capacitance forms a corner frequency beyond the resonance frequency of the sensor. For a flat frequency response a corner frequency well below the resonance frequency is recommended. In general the smallest possible bandwidth for an particular application should be chosen to get the best results. 8/14 LIS3L02AS5 3 3 Functionality Functionality The LIS3L02AS5 is a high performance, low-power, analog output three axes linear accelerometer packaged in a 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. 3.1 Sensing element A proprietary process is used 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 are free to move in the direction of the sensed acceleration. To be compatible with the traditional packaging techniques a cap is placed on top of the sensing element to avoid blocking the moving parts during the moulding phase of the plastic encapsulation. When an acceleration is applied to the sensor the proof mass displaces from its nominal position, causing an imbalance in the capacitive half-bridge. This imbalance is measured using charge integration in response to a voltage pulse applied to the sense capacitor. At steady state the nominal value of the capacitors are few pF and when an acceleration is applied the maximum variation of the capacitive load is up to 100fF. 3.2 IC Interface In order to increase robustness and immunity against external disturbances the complete signal processing chain uses a fully differential structure. The final stage converts the differential signal into a single-ended one to be compatible with the external world. The signals of the sensing element are multiplexed and fed into a low-noise capacitive charge amplifier that implements a Correlated Double Sampling (CDS) at its output to cancel the offset and the 1/f noise. The output signal is de-multiplexed and transferred 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 (zero-g level, sensitivity and self-test) are ratiometric to the supply voltage. Increasing or decreasing the supply voltage, the sensitivity and the offset will increase or decrease almost linearly. The self test voltage change varies cubically with the supply voltage. 3.3 Factory calibration The IC interface is factory calibrated for Sensitivity (So) and Zero-g Level (Voff). 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. This allows the user to employ the device without further calibration. 9/14 LIS3L02AS5 4 Application hints 4 Figure 3. Application hints LIS3L02AS5 Electrical Connection Vdd 10µF GND DIRECTION OF THE DETECTABLE ACCELERATIONS 100nF GND GND LIS3L02AS5 (top view) X 13 GND ST Y PD FS 1 Optional Vout Z Z Cload z Optional Vout X Cload x Optional Cload y Vout Y Digital signals Power supply decoupling capacitors (100nF ceramic or polyester + 10µF Aluminum) should be placed as near as possible to the device (common design practice). The LIS3L02AS5 allows to band limit Voutx, Vouty and Voutz through the use of external capacitors. The re-commended frequency range spans from DC up to 1.5 KHz. In particular, capacitors must be added at output pins to implement low-pass filtering for antialiasing and noise reduction. The equation for the cut-off frequency (ft) of the external filters is: 1 f t = -----------------------------------------------------------------2π ⋅ R out ⋅ C load ( x, y, z ) Taking in account that the internal filtering resistor (Rout) has a nominal value equal to 110kΩ, the equation for the external filter cut-off frequency may be simplified as follows: 1.45µF f t = ------------------------------------- [ Hz ] C load ( x, y, z ) The tolerance of the internal resistor can vary typically of ±20% within its nominal value of 110kΩ; thus the cut-off frequency will vary accordingly. A minimum capacitance of 320pF for Cload(x, y, z) is required in any case. 10/14 LIS3L02AS5 4 Application hints Table 5. 4.1 Filter Capacitor Selection, Cload (x,y,z). Cut-off frequency Capacitor value 1 Hz 1500 nF 10 Hz 150 nF 20 Hz 68 nF 50 Hz 30 nF 100 Hz 15 nF 200 Hz 6.8 nF 500 Hz 3 nF Soldering information The SO24 package is lead free qualified for soldering heat resistance according to JEDEC JSTD-020C. 4.2 Output response vs orientation Figure 4. Output response vs orientation Top Bottom X=1.50V (-1g) Y=2.50V (0 g) Z=2.50V (0g) X=2.50V (0g) Y=3.50V (+1g) Z=2.50V (0g) TOP VIEW X=2.50V (0g) Y=2.50V (0g) Z=1.50V (-1g) Top Bottom X=2.50V (0g) Y=2.50V (0g) Z=3.50V (+1g) X=2.50V (0g) Y=1.50V (-1g) Z=2.50V (0g) X=3.50V (+1g) Y=2.50V (0g) Z=2.50V (0g) Earth’s Surface Figure 4 refers to LIS3L02AS5 device powered at 5.0V 11/14 LIS3L02AS5 5 Package Information 5 Package Information In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a Lead-free second level interconnect. The category of second Level Interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com. Figure 5. SO24 Mechanical Data & Package Dimensions mm inch DIM. MIN. TYP. MAX. MIN. TYP. MAX. A 2.35 2.65 0.093 0.104 A1 0.10 0.30 0.004 0.012 B 0.33 0.51 0.013 0.200 C 0.23 0.32 0.009 0.013 D (1) 15.20 15.60 0.598 0.614 E 7.40 7.60 0.291 0.299 e 1.27 10.0 10.65 0.394 0.419 h 0.25 0.75 0.010 0.030 L 0.40 1.27 0.016 0.050 ddd Weight: 0.60gr 0.050 H k OUTLINE AND MECHANICAL DATA 0˚ (min.), 8˚ (max.) 0.10 0.004 (1) “D” dimension does not include mold flash, protusions or gate burrs. Mold flash, protusions or gate burrs shall not exceed 0.15mm per side. SO24 0070769 C 12/14 LIS3L02AS5 6 6 Revision history Revision history Date Revision 1-Dec-2005 1 Changes Initial release. 13/14 LIS3L02AS5 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. 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