New applications for linear output Hall effect sensing, such as displacement, angular position, and current measurement, require high accuracy in conjunction with small package size. The Allegro® A138x family of programmable linear Hall effect sensor ICs was designed specifically to achieve both goals. These temperature-stable devices are available in a miniature surface mount package (SOT23-W) and an ultramini throughhole single-in-line package. The accuracy of these devices is enhanced via programmability on the output pin for end-of-line optimization without the added complexity and cost of a fully programmable device.
These ratiometric Hall effect devices provide a voltage output that is proportional to the applied magnetic field. Both the quiescent voltage output and magnetic sensitivity are useradjustable. The quiescent voltage output can be set around 50% of the supply voltage, and the sensitivity adjusted between 2 mV/G and 9 mV/G over the device family. Programming selections also exist for output polarity and temperature compensation. The features of this linear family make it ideal for high accuracy requirements of automotive and industrial applications, and performance is guaranteed over an extended temperature range, –40°C 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.