This part is a kind of semiconductor called A3977KED.

Function of this product has MICROSTEPPING DMOS DRIVER WITH TRANSLATOR.

Manufacturers : Allegro MicroSystems

Image and pinout :

Some of the text within the PDF file :

3977 A3977xED (PLCC) LOAD SUPPLY 1 SENSE 1 ENABLE OUT 1A HOME GND GND GND SLEEP OUT 1B MICROSTEPPING DMOS DRIVER WITH TRANSLATOR The A3977xED and A3977xLP are complete microstepping motor drivers with built-in translator. They are designed to operate bipolar stepper motors in full-, half-, quarter-, and eighth-step modes, with output drive capability of 35 V and ±2.5 A. The A3977 includes a fixed off-time current regulator that has the ability to operate in slow-, fast-, or mixed-decay modes. This currentdecay control scheme results in reduced audible motor noise, increased step accuracy, and reduced power dissipation. The translator is the key to the easy implementation of the A3977. By simply inputting one pulse on the STEP input the motor will take one step (full, half, quarter, or ei [ ... ]

A3977KED PDF Datasheet Download