The A3422xKA Hall-effect, direction-detection sensor is a new generation of special function integrated sensors that are capable of sensing the direction of rotation of a ring magnet. These transducers provide separate digital outputs that provide information on magnet rotation speed, direction, and magnet pole count. These devices eliminate the major manufacturing hurdles encountered in fine-pitch direction-detection applications, namely maintaining accurate mechanical location between the two active Hall elements. Here, the two Hall elements are photolithographically aligned to better than 1 µm, as contrasted with 100 µm or worse mechanical location tolerance when manufactured discretely. These highly sensitive, temperature-stable, magnetic transducers are ideal for use in digital-encoder systems in the harsh environments of automotive or industrial applications. The A3422xKA is a high-sensitivity device optimized for use with high-density magnets.

The A3422xKA monolithic integrated circuit contains two independent Hall-effect latches whose digital outputs are internally coupled to CMOS logic circuitry that decodes signal speed and direction. Extremely low-drift BiCMOS circuitry is used for the amplifiers to ensure symmetry between the two latches so that signal quadrature can be maintained. An on-chip voltage regulator allows the use of these devices from a 4.5 V to 18 V supply. This device has standard open-collector outputs.

Functional Block Diagram