Programmable-sensitivity, linear Hall-effect sensor IC spans industrial temperature range

January 22, 2014 // By Graham Prophet
The A1304 from Allegro MicroSystems Europe is a linear Hall-effect sensor IC specifically designed for applications that require medium accuracy in a very small package: for applications in consumer and industrial markets, it has an industrial temperature range of -40°C to 85°C.

The A1304 is a factory trimmed one-time programmable 3.3V linear sensor that eliminates the need for users to programme the device to compensate for temperature effects on sensor performance. It has a typical programmable sensitivity level of 4 mV/G ± 6%.

The device’s high bandwidth and high-speed chopping scheme minimise quiescent voltage output drift across the operating temperature range, yielding a low noise analogue output and ultimately enabling higher accuracy.

The A1304 is a more cost-effective solution for non-automotive markets, with sensitivity and quiescent voltage output temperature coefficient being trimmed at the factory for improved accuracy relative to other low cost linear IC’s from Allegro (A1301/02).

The A1304 is fabricated in a monolithic BiCMOS process, and integrates a Hall element, offset and sensitivity trim circuitry to correct for the variation in the Hall element, a small-signal high-gain amplifier, and a proprietary dynamic offset cancellation technique. The temperature-stable ratiometric Hall-effect sensor provides a voltage output that is proportional to the applied magnetic field, and features a quiescent voltage output of 50% of the supply voltage.

Use it in cost-sensitive, space-constrained applications where two travel endpoints can be measured and a transfer function calibration performed by a microcontroller. Through this calibration routine an application can tolerate higher sensitivity variation from the linear IC and can therefore use a medium-accuracy sensor IC such as the A1304.

Specific target applications include linear proximity sensing in toys and gaming devices, smart electricity meters with tamper detection, power tools, white good appliances, actuators, and non-contact potentiometers.

It comes in a 3-pin miniature surface mount SOT-23W style package that supports small form-factor sensor assembly requirements (LH suffix).

Allegro MicroSystems;