A139x Series Micropower Linear Hall Effect Sensor IC

Allegro's A139x family of linear Hall effect sensor integrated circuits (ICs) provide a voltage output directly proportional to an applied magnetic field. Before amplification, the sensitivity of typical Hall effect ICs (measured in mV/G) is directly proportional to the current flowing through the Hall effect transducer element inside the ICs. In many applications, achieving sufficient sensitivity levels with a Hall effect sensor IC is difficult without consuming more than 3 mA of current. The A139x ICs minimize current consumption to less than 25 µA by adding a user-selectable sleep mode, making these devices perfect for battery-operated applications such as cellular phones, digital cameras, and portable tools. End users can control the current consumption of the A139x by applying a logic-level signal to the SLEEP pin. The outputs of the devices are not valid (high impedance mode) during sleep mode. The high-impedance output feature allows the connection of multiple A139x Hall effect devices to a single A-to-D converter input. The quiescent output voltage of these devices is 50% nominal of the ratiometric supply reference voltage applied to the V_REF pin of the device. The output voltage of the device is not ratiometric with respect to the SUPPLY pin.

Despite the low power consumption of the circuitry in the A139x, the features required to produce a highly accurate linear Hall effect IC have not been compromised. Each BiCMOS monolithic circuit integrates a Hall element, improved temperature-compensating circuitry to reduce the intrinsic sensitivity drift of the Hall element, a small-signal high-gain amplifier, and proprietary dynamic offset cancellation circuits. End-of-line, post-packaging, factory programming allows precise control of device sensitivity and offset. These devices are available in a small 2.0 mm × 3.0 mm, 0.75 mm nominal height micro-leaded package (MLP/DFN). It is Pb (lead)-free, with 100% matte tin leadframe plating.