Programmable Hall-effect sensor

The linear potentiometer is elegant in its simplicity, yet is versatile for a broad range of automotive, aerospace, industrial and medical applications. The shortcomings are in the device's longevity -- they are prone to dirt infiltration and, as an electromechanical device, eventually become unreliable due to wear.

The HAL 805 is part of a family of programmable linear Hall sensors from Micronas Semiconductors, San Jose, CA. It can be used for angle or distance measurements if combined with a rotating or moving magnet. The contactless design is minimally affected by dirt or wear, and works well in environments with high vibrations, high temperatures, changing supply voltages and electromagnetic interference. The programming is handled through modulation of the supply voltage -- simpler than mechanical adjustments or laser trimming. This means that automatic electronic in-line adjustments can be made on a production line. An internal digital signal processor avoids the analog offsets, temperature shifts and mechanical stresses that plague standard pots. Programmable on-chip digital signal processing allows sensors to be individually adjusted to different requirements and applications.

Individual programming provides the ability to place HAL 850 sensors in groups running in parallel to the same supply voltage. Each sensor can then be selected via its output pin. The non-volatile EEPROM memory has built-in redundancy and lock functions.

The sensor also features diagnostic functions for open circuit detection, plus overvoltage and reverse-voltage protection at all pins. Integrated compensation and protection circuitry allows the device to operate with static and dynamic fields of up to 2 kHz. It operates in temperatures ranging from -40 to 150°C, and has been optimized for automotive applications such as throttle position and electronic pedal sensors. The HAL 805 is capable of replacing existing components in a system without having to change the system environment.

--RM

For more information: Circle 555 - Micronas Semiconductors, Inc., or connect directly to their website via the Online Reader Service Program at http://www.1rs.com/006df-555