Linear Hall-effect sensor IC is user-programmable

Paul Boughton

Allegro Microsystems Europe is launching the A1386 user-programmable linear Hall-effect sensor IC, which is targeted at applications in the automotive market requiring flexibility and accuracy in absolute position sensing.

According to Allegro, the device is unique in offering dual operating modes: normal and low-power. In normal mode, the A1386 operates as a highly accurate, user-programmable linear sensor with ratiometric output. In low-power mode, the device disengages some internal components to reduce power consumption. Although its accuracy is compromised during low-power operation, the sensor can still be used as a region indicator - to detect the north or south pole of a rotating ring magnet.

The A1386 is based on a BiCMOS monolithic circuit that integrates a Hall element and temperature-compensation to reduce the intrinsic sensitivity drift of the Hall element, a small-signal high-gain amplifier, a clamped low-impedance output stage, and proprietary dynamic offset cancellation circuitry.

Output is an analogue voltage signal that is proportional to the applied magnetic field over the entire 5V supply range. Both the quiescent voltage output and the magnetic sensitivity are user-adjustable. The quiescent voltage output can be set to approximately 50 per cent of the supply voltage, and the sensitivity can be adjusted between 1.90mV/G and 3.50mV/G for a forward supply voltage of 5 V.

The quiescent voltage and sensitivity are extremely stable against temperature variations, which minimises the risk of output drift and the resulting output errors. The temperature coefficient sensitivity of the A1386 is factory-programmed to 0.13 per cent/degree C, meaning the devices are optimised for use with neodymium magnets with no need for user adjustment.

An important feature of the A1386 is its ability to recognise when the forward supply voltage drops below a certain voltage threshold, at which point the device operates at a nominal 3V and both the quiescent voltage output and sensitivity are scaled ratiometrically. The device is most accurate at a nominal 5V.

These features make the A1386 suitable for high-accuracy sensing in automotive and industrial applications, with guaranteed performance over an extended temperature range of -40 to +150 degrees C.

The A1386 is available in an ultra miniature through-hole single-inline package (UA suffix) or a miniature surface mount package (LH suffix).

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