L20G20IS STMICROELECTRONICS | Alldatasheet
Document overview
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- PDF pages: 29
Technical content
Datasheet sections
- 1 Block diagram and pin description
- 1.1 System block diagram
- 1.2 Pin description
- 2 Mechanical and electrical specifications
- 2.1 Mechanical characteristics
- 2.2 Electrical characteristics
- 2.3 Temperature sensor characteristics
- 2.4 SPI - serial peripheral interface
- 2.5 Absolute maximum ratings
- 3 Terminology and functionality
- 3.1 Sensitivity
- 3.2 Zero-rate level
- 3.3 Data-ready interrupt and synchronous reading
- 3.4 Temperature sensor
- 4 L20G20IS filtering chain
- 5 Application hints
- 5.1 Internal pin status
- 6 Digital interfaces
- 6.1 SPI bus interface
- 6.1.1 SPI read
- 6.1.2 SPI write
- 7 Register mapping
- 8 Register description
- 8.1 WHO_AM_I (00h R)
- 8.2 TEMP_OUT_L (01h R), TEMP_OUT_H (02h R)
- 8.3 OUT_X_L (03h R), OUT_X_H (04h R)
Features
±100 dps / ±200 dps full-scale range 5 degree phase delay 3.8 mdps/√(Hz) rate noise density Wide supply voltage range: 1.7 V to 3.6 V Low-voltage compatible IOs 3- and 4-wire SPI digital interface Embedded temperature sensor Embedded self-test Integrated low-pass filters with user-selectable bandwidth Power-down and sleep modes for smart power saving ECOPACK®, RoHS and “Green” compliant
Applications
Optical image stabilization
Description
The L20G20IS is a two-axis MEMS gyroscope for optical image stabilization applications. It includes a sensing element and an IC interface capable of providing the measured angular rate to the application through an SPI digital interface. The unique sensing element is manufactured using a dedicated micromachining process developed by STMicroelectronics to produce inertial sensors and actuators on silicon wafers. The IC interface is manufactured using a CMOS process that allows a high level of integration to design a dedicated circuit which is trimmed to better match the characteristics of the sensing element. The L20G20IS is available in a plastic land grid array (LGA) package and can operate over a temperature range of -40 °C to +85 °C. LGA-12 (2.0 x 2.0 x 0.7 mm) Table 1. Device summary
1 Block diagram and pin description
1.1 System block diagram
Figure 1. Block diagram
1.2 Pin description
Figure 2. Pin connections
- Leave pin electrically unconnected and soldered to PCB.
Table 2. Pin description
1 VDDIO Power supply for I/O pins
2 SCL Clock line for SPI interface
3 SDI/SDO Serial data input (SDI) 3-wire interface serial data output (SDO)
4 SDO Serial data output (SDO)
5 CS Chip-select line
6 DRDY Data ready signal
7 RES
- Leave pin electrically unconnected and soldered to PCB.
8 RES Connect to GND
9 RES Connect to GND
10 GND 0 V power supply
11 REG Capacitance connection pin for internal regulator
12 VDD Power supply
2 Mechanical and electrical specifications
2.1 Mechanical characteristics
Table 3. Mechanical characteristics TDVoff Digital zero-rate level drift vs.
- Typical specifications are not guaranteed.
- Sensitivity value after factory calibration test and trimming.
- Measurements are performed in a uniform temperature setup and they are based on characterization data with a limited
number of samples, not measured during final test production.
- Zero-rate level value after factory calibration test and trimming.
- Refer to Section 4: L20G20IS filtering chain for filtering details.
2.2 Electrical characteristics
Table 4. Electrical characteristics
2.3 Temperature sensor characteristics
Table 5. Temperature sensor characteristics
- Typical specifications are not guaranteed
- 4 mA is the maximum driving capability, i.e. the maximum DC current that can be sourced/sunk by the digital pad in order to
guarantee the correct digital output voltage levels VOH and VOL.
- Typical specifications are not guaranteed
- The output of the temperature is 0 at 25 °C.
2.4 SPI - serial peripheral interface
Subject to general operating conditions for Vdd and Top. Figure 3. SPI slave timing diagram Table 6. SPI slave timing values
- Values are guaranteed at 10 MHz clock frequency for SPI, based on characterization results, not tested in production.
2.5 Absolute maximum ratings
Note: Supply voltage on any pin should never exceed 4.8 V. Table 7. Absolute maximum ratings permanent damage to the part. cause permanent damage to the part.
Terminology and functionality L20G20IS
3 Terminology and functionality
3.1 Sensitivity
An angular rate gyroscope is a device that produces a positive-going digital output for counterclockwise rotation around the sensitive axis considered. Sensitivity describes the gain of the sensor and can be determined by applying a defined angular velocity to it. This value changes very little over temperature and time.
3.2 Zero-rate level
The zero-rate level describes the actual output signal if there is no angular rate present. The zero-rate level of highly accurate MEMS sensors is, to some extent, a result of stress to the sensor and therefore the zero-rate level can slightly change after mounting the sensor on a printed circuit board or after exposing it to extensive mechanical stress. This value changes very little over temperature and time.
3.3 Data-ready interrupt and synchronous reading
On the L20G20IS the angular rate data can be retrieved using a synchronous read. To perform a synchronous read, CTRL4_OIS (0Eh R/W) (DRDY_EN) has to be set to '1' in order to enable the data-ready interrupt on the DRDY pin (refer to Figure 5). To properly perform a synchronous read, the angular rate data have to be read every time the DRDY pin goes high. The DRDY signal can be latched (default condition) or pulsed if CTRL1_OIS (0Bh R/W)(DR_DRDY) is set to '1'. When a latched condition is selected, the interrupt goes low when the high part of one of the output channels is read X-axis angular rate data. The value is expressed as two’s complement. or DATA_STATUS_OIS (0Ah R) and returns high when new data is generated. When a pulsed condition is selected, the interrupt behavior is independent from the read operations and remains high for 75 μsec every time new data is generated. The DRDY pin is set by default as push-pull output, but it can be configured as open-drain output by setting CTRL4_OIS (0Eh R/W) (DRDY_OD) to '1'.
3.4 Temperature sensor
The temperature data can be retrieved from the TEMP_OUT_L (01h R), TEMP_OUT_H (02h R) registers, as two's complement data in 12-bit format left-justified. The output of the temperature sensor is 0 at 25 °C.
4 L20G20IS filtering chain
The filtering chain for the L20G20IS appears in the figure below. Figure 4. Filtering chain block diagram Table 8. Digital LPF configuration Table 9. Digital HPF configuration
5 Application hints
Figure 5. L20G20IS electrical connections
- Leave pin electrically unconnected and soldered to PCB.
supply pins on the device (common design practice).
5.1 Internal pin status
Table 10. Internal pin status
2 SCL Clock line for SPI interface Default: input without pull-up
3 SDI/SDO Serial data input (SDI)
4 SDO Serial data output (SDO) Default: input without pull-up
5 CS Chip-select line Default: input without pull-up
6 DRDY Data ready signal Default: push-pull to gnd
7 RES Leave unconnected Default: push-pull to gnd
8 RES Connect to GND Internally unconnected
9 RES Connect to GND Internally unconnected
6 Digital interfaces
6.1 SPI bus interface
The SPI is a bus slave. The SPI allows to write and read the registers of the device. The serial interface connects to applications using 4 wires: CS, SCL, SDI and SDO. falling edge of SCL and should be captured at the rising edge of SCL. from the device is read. In latter case, the chip will drive SDO at the start of bit 8. bit 1-7: address AD(6:0). This is the address field of the indexed register. bit 8-15: data DI(7:0) (write mode). This is the data that is written into the device (MSb first). bit 8-15: data DO(7:0) (read mode). This is the data that is read from the device (MSb first). The function and the behavior of SDI and SDO remain unchanged. Table 11. Serial interface pin description
6.1.1 SPI read
Figure 6. SPI read protocol bit 0: READ bit. The value is 1. bit 2-7: address AD(5:0). This is the address field of the indexed register. A multiple read command is also available.
6.1.2 SPI write
Figure 7. SPI write protocol is performed by adding blocks of 8 clock pulses to the previous one. bit 0: WRITE bit. The value is 0. bit 2 -7: address AD(5:0). This is the address field of the indexed register. Figure 8. Multiple byte SPI write protocol (2-byte example)
7 Register mapping
write the data through the serial interface. Table 12. Register address map permanent damage to the device. table must not be accessed and the content stored in those registers must not be changed.
8 Register description
write the data through the serial interface.
8.1 WHO_AM_I (00h R)
8.2 TEMP_OUT_L (01h R), TEMP_OUT_H (02h R)
8.3 OUT_X_L (03h R), OUT_X_H (04h R)
X-axis angular rate data. The value is expressed as two’s complement.
8.4 OUT_Y_L (05h R), OUT_Y_H (06h R)
Y-axis angular rate data. The value is expressed as two’s complement. Table 13. WHO_AM_I register Table 14. TEMP_OUT_L register Table 15. TEMP_OUT_H register Table 16. TEMP_OUT resolution Temp11-Temp0 Temperature data. temperature sensor output data.
8.5 DATA_STATUS_OIS (0Ah R)
8.6 CTRL1_OIS (0Bh R/W)
Table 17. DATA_STATUS_OIS register Table 18. DATA_STATUS_OIS description Table 19. CTRL1_OIS register Table 20. CTRL1_OIS register description
- Boot request is executed as soon as internal oscillator is turned on. It is possible to set this bit while in
power-down mode in which case it will be served at the next normal mode or sleep mode.
8.7 CTRL2_OIS (0Ch R/W)
Table 24. Digital LPF configuration Table 21. Operating mode selection Table 22. CTRL2_OIS register
- This bit must be set to ‘0’ for proper operation of the device.
Table 23. CTRL2_OIS register description LPF_BW[1:0] Low-pass filter bandwidth selection. Refer to Figure 4 and Table 24.
8.8 CTRL3_OIS (0Dh R/W)
8.9 CTRL4_OIS (0Eh R/W)
8.10 OFF_X (0Fh R/W)
Table 30. OFF_X register description The calibration step is -0.98 dps/LSB. Table 25. CTRL3_OIS register
- These bits must be set to ‘0’ for proper operation of the device
Table 26. CTRL3_OIS register description LPF_BW2 Low-pass filter bandwidth selection. Refer to Figure 4 and Table 24. Table 27. CTRL4_OIS register
- These bits must be set to ‘0’ for proper operation of the device.
Table 28. CTRL4_OIS register description Temperature data-ready signal on DRDY pad. Table 29. OFF_X register
- This bit must be set to ‘0’ for proper operation of the device
The value is expressed as two’s complement.
8.11 OFF_Y (10h R/W)
Table 31. OFF_Y register Table 32. OFF_Y register description Calibration step is 0.98 dps/LSB.
8.12 OIS_CFG_REG (1Fh R/W)
- This bit must be set to ‘0’ for proper operation of the device
Table 33. OIS_CFG register
- These bits must be set to ‘0’ for proper operation of the device
Table 34. OIS_CFG register description Table 35. Digital HPF configuration
9 Package information
specifications, grade definitions and product status are available at: www.st.com.
9.1 Soldering information
The LGA package is compliant with the ECOPACK®, RoHS and “Green” standard. It is qualified for soldering heat resistance according to JEDEC J-STD-020. Land pattern and soldering recommendations are available at www.st.com/mems.
9.2 LGA-12 package
Figure 9. LGA-12: package outline and mechanical data
9.3 LGA-12 packing information
Figure 10. Carrier tape information for LGA-12 package Figure 11. LGA-12 package orientation in carrier tape
Figure 12. Reel information for carrier tape of LGA-12 package Table 36. Reel dimensions for carrier tape of LGA-12 package
Table 37. Document revision history