Description
The A3981 is a flexible microstepping motor driver with built-in translator for easy operation. It is a single-chip solution, designed to operate bipolar stepper motors in full-, half-, quarter- and sixteenth-step modes, at up to 28 V and ±1.4 A. The A3981 can be controlled by simple Step and Direction inputs, or through the SPI-compatible serial interface that also can be used to program many of the integrated features and to read diagnostic information.

Features and Benefits
• Peak motor current up to ±1.4 A, 28 V
• Low RDS(on) outputs, 0.5 Ω source and sink, typical
• Automatic current decay mode detection/selection
• Mixed, Fast, and Slow current decay modes
• Synchronous rectification for low power dissipation
• Internal OVLO, UVLO, and Thermal Shutdown circuitry
• Crossover-current protection
• Short circuit and open load diagnostics
• Hot and cold thermal warning
• Stall detect features
• SPI-compatible or simple Step and Direction motion control
• Highly configurable via SPI-compatible serial interface

Applications
• Automotive stepper motors
• Engine management
• Headlamp positioning