A3977 Datasheet | Allegro MicroSystems

Microstepping DMOS Driver with Translator Features AND BENEFITS - ±2.5 A, 35 V output rating - Low RDS(on) outputs, 0.28 Ω source, 0.22 Ω sink typical - Automatic current decay mode detection/selection - 3.0 to 5.5 V logic supply voltage range - Mixed, fast, and slow current decay modes - Home output - Synchronous rectification for low power dissipation - Internal UVLO and thermal shutdown circuitry - Crossover-current protection Package: 28-pin TSSOP (suffix LP) with Exposed Thermal Pad Not to scale DESCRIPTION The A3977 is a plete microstepping motor driver with built-in translator. It is 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. Simply inputting one pulse on the STEP input drives the motor one step (two logic inputs determine if it is a full-, half-, quarter-, or eighth-step). There are no phase-sequence tables, high-frequency control lines, or plex interfaces to program. The A3977 interface is an ideal fit for applications where a plex microprocessor is unavailable or overburdened. Internal synchronous-rectification control circuitry is provided to improve power dissipation during PWM operation. Internal circuit protection includes thermal shutdown with hysteresis, undervoltage lockout (UVLO), and crossover-current protection. Special power-up sequencing is not required. The A3977 is supplied in a thin (<1.2 mm) 28-pin TSSOP with an exposed thermal pad (suffix LP). The A3977 is lead (Pb) free, with 100% matte tin leadframe plating. A3977-DS, Rev. 15 MCO-0000420 Pinout Diagram April 22, 2022 Microstepping DMOS Driver...