Sensor IC delivers medium accuracy in a small package

21st January 2014
Staff Reporter

Specifically designed for applications requiring medium accuracy in a small package, the A1304 from Allegro MicroSystems is a linear Hall-effect sensor IC. Supporting an industrial temperature range of -40°C to 85°C, the device is suitable for applications in consumer and industrial markets.


The factory trimmed, one-time programmable, 3.3 V linear sensor eliminates the need for customers to program the device to compensate for temperature effects on sensor performance. The sensor features a typical programmable sensitivity level of 4 mV/G ± 6%. The sensor's high-speed chopping scheme and bandwidth minimise quiescent voltage output drift across the operating temperature range, yielding a low noise analogue output and ultimately enabling higher accuracy.

Fabricated in a monolithic BiCMOS process, the device 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.

The A1304 is ideal for use 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 like the A1304. The device is a more cost-effective alternative to Allegro’s existing linear Hall-effect sensors, 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).

Linear proximity sensing in toys and gaming devices, smart electricity meters with tamper detection, power tools, white good appliances, actuators, and non-contact potentiometers are examples of suitable applications.

The device is available in a 3-pin miniature surface mount SOT-23W style package, thus supporting small form-factor sensor assembly requirements (LH suffix). The package is lead (Pb) free, with 100% matt tin leadframe plating.


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