3-Axis Digital Output Gyroscope

The I3G4250D is a 3-axis gyroscope with a digital output that STMicroelectronics is offering. This low-power, angular rate sensor provides unprecedented stability over time and temperature and unmatched sensitivity at zero-rate levels. Included in the I3G4250D is a sensing element along with a serial digital interface that transfers the measured angular rate to the application. This data transfer happens over a high-speed digital serial peripheral interface. In addition, the gyroscope comes with an I2C interface as well.

ST manufactures the sensing element in the gyroscope with a unique micromachining process. ST has developed this process for producing inertial actuators and sensors on wafers of silicon.

A CMOS IC provides the interface, allowing a high level of design integration necessary for building a dedicated circuit. Then they trim this to specifically match the sensing element’s characteristics. Users can select the full-scale output of the sensor to be ±245, ±500, or ±2000 DPS. Moreover, the user can also select the bandwidth for measuring the rates.

ST offers this gyroscope as a Land Grid Array or LGA package made of plastic. It is capable of operating within an ambient temperature range of -40 °C to +85 °C. The gyroscope has some unique features. It can tolerate a supply voltage variation of 2.4 VDC to 3.6 VDC. With two digital output interfaces of I2C and SPI, the sensor provides data output for rate value at 16 bits, and data output for temperature at 8 bits. For interfacing with outside circuits, the sensor offers two digital output lines—an interrupt and a data-ready output. Users can select the bandwidth of low- and high-pass filters integrated within the IC. The sensor offers exceptionally stable outputs over time and temperature.

With low-voltage compatible Input/Output lines, the IC can interface with digital signals of 1.8 VDC levels. Along with an embedded temperature sensor, the IC also has an embedded FIFO and also embeds power down and sleep modes. The sensor is ECOPACK, Green, and RoHS compliant, and can survive high shocks.

To evaluate the MEMS devices within the I3G4250D family, ST offers an adapter board— the STEVAL-MKI169V1. This adapter board matches a standard DIL socket, offering an effective solution for speedy system prototyping and evaluation of devices that the user is directly applying.

The user can directly plug in the adapter board in a standard DIL socket with 24 pins and take advantage of the complete I3G4250D pin-outs. The adapter board also comes with the necessary decoupling capacitors mounted on the VDD power supply pins.

ST supports this adapter board with its motherboard, the  STEVAL-MKI109V2. The motherboard has a powerful 32-bit microcontroller to act as a bridge between a PC and the sensor. ST also provides a graphical user interface—the Unico GUI— for the PC, which the user can download and use. They also provide dedicated software routines to customize the applications.

ST has targeted the I3G4250D 3-axis gyroscope with a digital output mainly for industrial applications. However, users can use the gyroscope for applications like navigational systems and telematics. The device is also useful in man-machine interfaces like motion control, and for various appliances like robotics.