Guidelines for using Allegro angular sensors

Many applications in different industries, such as in industrial automation and automotive sensors and actuators, require monitoring the angle of a rotating shaft either in an on-axis or off-axis arrangement. This application note is dedicated to a review of on-axis magnetic applications.

Magnetic sensor integrated circuits (ICs) are commonly used to perform this task. This document provides guidelines for using angle sensors based on the Circular Vertical Hall (CVH) technology, which is the core of each Allegro angular position sensor mentioned within this article.

The design of any angle measurement system is based on the needs of the particular application, such as air gap, accuracy, and temperature range, as well as the properties of the sensor. This document provides an introduction to magnet selection and an understanding of the influences that determine the accuracy of such systems.

A magnetic angle measurement system has two main sources of error:

• sensor IC related errors
• magnetic input related errors