This part is a kind of semiconductor called A3144-LT.

Function of this product has SENSITIVE HALL-EFFECT SWITCHES FOR HIGH-TEMPERATURE OPERATION.

Manufacturers : Allegro MicroSystems

Image and pinout :

Some of the text within the PDF file :

3141 THRU 3144 SENSITIVE HALL-EFFECT SWITCHES FOR HIGH-TEMPERATURE OPERATION These Hall-effect switches are monolithic integrated circuits with tighter magnetic specifications, designed to operate continuously over extended temperatures to +150°C, and are more stable with both temperature and supply voltage changes. The unipolar switching characteristic makes these devices ideal for use with a simple bar or rod magnet. The four basic devices (3141, 3142, 3143, and 3144) are identical except for magnetic switch points. Each device includes a voltage regulator for operation with supply voltages of 4.5 to 24 volts, reverse battery protection diode, quadratic Hall-voltage generator, temperature compensation circuitry, smallsignal amplifier, Schmitt trigger, and an open-collector output to si [ ... ]

A3144-LT PDF Datasheet Download