New Industry Products

Allegro Introduces User Programmable Linear Sensor To Automotive Market

February 01, 2009 by Jeff Shepard

Allegro has added a new device to their line of programmable linear sensors. This new sensor is targeted at the automotive market and is designed to be flexible and highly accurate in applications requiring absolute position sensing. It is claimed to be unique to the market due to its dual operating modes, normal and low power.

In normal operation mode Allegro’s A1386 operates as a user-programmable linear with ratiometric output. In low power mode, the device actually disengages some internal components to reduce power consumption. The accuracy of the device is also compromised during low power consumption but remains serviceable as a region indicator (north or south pole of a rotating ring magnet).

These ratiometric Hall-effect sensors provide a voltage output that is proportional to the applied magnetic field over the entire 5.0V supply. Both the quiescent voltage output and the magnetic sensitivity are user adjustable. The quiescent voltage output can be set to approximately 50% of the supply voltage, and the sensitivity adjusted between 1.90 mV/G and 3.50 mV/G for Vcc = 5V. The sensitivity TC of the A1386 is programmed in the factory to 0.13 %/°C to compensate for neodymium magnets. An important feature of this device is its ability to recognize when Vcc drops below a certain voltage threshold at which time the device operates at a nominal 3V and both the quiescent voltage output and sensitivity scale ratiometrically. The device is most accurate at a nominal 5V. These features make this device suitable for high accuracy requirements of automotive and industrial applications guaranteeing performance over an extended temperature range of 40 to 150°C.

Each BiCMOS monolithic circuit integrates a Hall element, temperature-compensating circuitry to reduce the intrinsic sensitivity drift of the Hall element, a small-signal high-gain amplifier, a clamped low impedance output stage, and a proprietary dynamic offset cancellation technique.

Allegro’s A1386 is available in an ultra miniature (UA suffix) through-hole single-inline package priced at $1.17 in quantities of 1,000 and a miniature surface mount package (LH) priced at $1.16 in quantities of 1,000. Both have a 14-week lead-time to market.