This part is a kind of semiconductor called A3989.

Function of this product has Bipolar Stepper and High Current DC Motor Driver.

Manufacturers : Allegro MicroSystems

Image and pinout :

Some of the text within the PDF file :

A3989 Bipolar Stepper and High Current DC Motor Driver Features and Benefits ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ 36 V output rating 2.4 A dc motor driver 1.2 A bipolar stepper driver Synchronous rectification Internal undervoltage lockout (UVLO) Thermal shutdown circuitry Crossover-current protection Very thin profile QFN package Description The A3989 is designed operate at voltages up to 36 V while driving one bipolar stepper motor, at currents up to 1.2A, and one dc motor, at currents up to 2.4 A. The A3989 includes a fixed off-time pulse width modulation (PWM) regulator for current control. The stepper motor driver features dual 2-bit nonlinear DACs (digital-to-analog converters) that enable control in full, half, and quarter steps. The dc motor is controlled using standard PHASE a [ ... ]

A3989 PDF Datasheet Download