LIS3L06AL_06 STMICROELECTRONICS | Alldatasheet
Document overview
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- PDF pages: 17
Technical content
Datasheet sections
- 1 Block Diagram & Pins Description
- 1.1 Block diagram
- 1.2 Pin Description
- 2 Mechanical and Electrical Specifications
- 2.1 Mechanical Characteristics
- 2.2 Electrical Characteristics
- 2.3 Absolute maximum ratings
- 2.4 Terminology
- 3 Functionality
- 3.1 Sensing element
- 3.2 IC Interface
- 3.3 Factory calibration
- 4 Application hints
- 4.1 Soldering information
- 4.2 Output Response vs Orientation
- 5 Typical performance characteristi cs
- 5.1 Mechanical Characteristics at 25°C
- 5.2 Mechanical Characteristics derived from measurement in the
- 5.3 Electrical characteristics at 25°C
- 6 Package Information
- 7 Revision history
Features
■ 2.4V to 3.6V single supply operation ■ Low power consumption ■ ±2g/±6g user selectable full-scale ■ 0.5mg resolution over 100hz bandwidth ■ Embedded self test ■ Output voltage, offset and sensitivity ratiometric to the supply voltage ■ High shock survivability ■ ECOPACK® Lead-free compliant (see Section 6)
Description
The LIS3L06AL is a low-power 3-axis linear capacitive 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 to design a dedicated circuit which is trimmed to better match the sensing element characteristics. The LIS3L06AL has a dynamically selectable full scale of ±2g/±6g and it is capable of measuring accelerations over a bandwidth of 1.5 kHz 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 LIS3L06AL is available in plastic SMD package and it is guaranteed to operate over an extended temperature range of -40°C to +85°C. The LIS3L06AL 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 LGA-8 Part number Temp range, °CP a c k a g e P a c k i n g LIS3L06AL -40°C to +85°C LGA-8 Tray LIS3L06ALTR -40°C to +85°C LGA-8 Tape & Reel
1 Block Diagram & Pins Description
1.1 Block diagram
Figure 1. Block Diagram
1.2 Pin Description
Figure 2. Pin Connection
Table 1. Pin description
1 ST Self Test (Logic 0: normal mode; Logic 1: Self-test)
2 Voutz Output Voltage Z channel
3 GND 0V supply
4 Reserved Leave unconnected
5 FS Full Scale (Logic 0:2g Full scale; Logic1: 6g Full Scale)
6 Vouty Output Voltage Y channel
7 Voutx Output Voltage X channel
8 Vdd Power supply
2 Mechanical and Electrical Specifications
2.1 Mechanical Characteristics . Table 2. Mechanical Characteristics (1)
2.2 Electrical Characteristics
- Typical specificat ions are not guaranteed
- Guaranteed by wafer level test and measurement of initial offset and sensitivity
- Zero-g level and sensitivity are ess entially ratiometric to supply voltage
- Contribution to the measuring output of the inclination/acceleration along any perpendicular axis
- Self test “output voltage change” is defined as Vout
- Self test “output voltage change” va ries cubically with supply voltage
- When Full Scale is set to ±6g, “self test ou tput change” is one third of the corresponding ±2g range.
- Minimum resonance frequency Fres=1.5kHz. Sensor bandwidth=1/(2*π*110kΩ*Cload) with Cload>1nF.
Table 3. Electrical Characteristics (1)
- The product is factory calibrated at 3.3V
- Typical specificat ions are not guaranteed
- Minimum resonance frequency Fres =1.5KHz. Sensor bandwidth=1/(2*π*110kΩ*Cload) with Cload>1nF
Table 2. Mechanical Characteristics (1) (continued)
2.3 Absolute maximum ratings
2.4 Terminology
little over temperature (see sensitivity change vs. temperature) and also very little over time. tolerance describes the range of Zero-g levels of a population of sensors. Table 4. Absolute maximum ratings
Mechanical and Electrical Specifications LIS3L06AL 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 1nF 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.
3 Functionality
The LIS3L06AL is a high performance, low-power, analog output 3-axis linear accelerometer packaged in a LGA 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 system (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.
4 Application hints
Figure 3. LIS3L06AL Electrical Connection be placed as near as possible to the device (common design practice). Cload(x, y, z) is required in any case. Table 5. Filter Capacitor Selection, C load (x,y,z)
1 Hz 1500 nF
10 Hz 150 nF
20 Hz 68 nF
50 Hz 30 nF
100 Hz 15 nF
500 Hz 3 nF
4.1 Soldering information
qualified for soldering heat resistance according to JEDEC J-STD-020C. Land pattern and soldering recommendations are available upon request.
4.2 Output Response vs Orientation
Figure 4. Output response vs Orientation Figure 4 refers to LIS3L06AL device powered at 3.3V.
5 Typical performance characteristics
5.1 Mechanical Characteristics at 25°C
Figure 5. x-axis Zero-g level at 3.3V Figure 6. x-axis sensitivity at 3.3V Figure 7. y-axis Zero-g level at 3.3V Figure 8. y-axis sensitivity at 3.3V Figure 9. z-axis Zero-g level at 3.3V Figure 10. z-axis sensitivity at 3.3V
5.2 Mechanical Characteristics de rived from measurement in the
Figure 11. x-axis Zero-g level change Vs Figure 12. x-axis sensitivity change Vs Figure 13. y-axis Zero-g level change Vs Figure 14. y-axis sensitivity change Vs Figure 15. z-axis Zero-g level change Vs Figure 16. z-axis sensitivity change Vs
5.3 Electrical characteristics at 25°C
Figure 17. Noise density at 3.3V (x,y axis) Figure 18. Noise density at 3.3V (z axis) Figure 19. Current Consumption at 3.3V
6 Package Information
conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com. Figure 20. LGA-8 Mechanical Data & Package Dimensions
7 Revision history
Table 6. Document revision history 28-Sep-2005 1 Initial release. 03-May-2006 2 Corrected typo errors. Applied new corporate template layout.