STMicroelectronics has introduced the market’s first 3-axis digital-output gyroscope meeting the AEC-Q100, the industry-standard qualification specification detailing a set of stress tests and defining the qualification needs for integrated circuits (ICs) in automotive applications. ST’s newest angular-rate sensor aims to add positioning accuracy and stability to a wide range of automotive applications, including in-dash navigation, telematics and vehicle tolling systems.
Accurate measurements of angular-motion detection with ST’s automotive-qualified gyroscopes will improve dead-reckoning and/or map-matching capabilities in car navigation and telematics applications. In situations when a GPS signal can’t be seen, such as indoors and in urban canyons between tall buildings, dead-reckoning systems compensate for loss of satellite signal by monitoring motion, distance traveled and altitude.
Precise gyroscope readings can also improve map-matching, the process of aligning a sequence of observed user positions with the road network on a digital map, used in a number of applications, including traffic flow analysis and driving directions.
These new dead-reckoning and map-matching capabilities are enabled with the design concept of ST’s gyroscopes, which employ a single sensing structure for motion measurement along all three orthogonal axes.[There are three main types of angular motion: yaw is rotation around the vertical axis; roll is rotation around the front-to-back axis and pitch is the rotation around the side-to-side axis]. This eliminates any interference between the axes, significantly increasing measurement precision, coupled with excellent output stability over time and temperature.
ST’s A3G4250D gyroscope measures angular rates up to +/-250dps (degree per second). An on-chip IC interface converts the angular-motion data into a 16-bit digital bit stream that is transmitted with high reliability to a dedicated microcontroller chip through a standard SPI or I2C protocol. The device provides two output lines (interrupt and data ready) and four user-selectable output data rates.
The 3V single-supply sensor integrates power-down and sleep modes and an embedded FIFO (first-in first-out) memory block for smarter power management. The A3G4250D embeds an 8-bit temperature sensor and operates within an extended temperature range from -40 to 85°C. The device is robust to electromagnetic interference and withstands shocks up to 10,000g.
The gyroscope has been designed and produced using the same manufacturing-process technology that ST has already successfully applied to 1.8 billion motion sensors sold in the market. Samples of ST’s A3G4250D are available and volume production will start by Q2 2012. Unit pricing is $6 for volumes in the range of 1,000 pieces.