The A3981 is a programmableMicrostepping motor driver, with a built-in converter for easy operation. It is a single-chip solution that can be used in full-step, half-step, quarter-step, and sixteenth-step modesDrive a bipolar stepper motorOperating voltages and currents up to 28 V and ±750 mA. The A3981 can be controlled using simple step and direction inputs or via an SPI-compatible interface, and can be used to set up a variety of integration functions and read diagnostic information.
The current regulator can be programmed to operate with fixed downtime or fixed frequency PWM, and can reduce audible motor noise and improve step accuracy with multiple attenuation modes. Furthermore, phase ammeters can be programmed via a serial interface to establish the appropriate microstep current distribution for a specific application, further improving motor performance.
All phase currents of the motor are controlled by a DMOS full-bridge unit using synchronous rectification to reduce power dissipation. When switching between high-side drive and low-side drive, internal circuitry and timer prevent transconductance and breakdown,
This avoids output short circuits. In addition, it features low load current and stall rotor detection. Chip-level protection includes: high and low temperature warnings, overtemperature shutdown, overvoltage and undervoltage lockout.
apply
- Automotive stepper motor
- Engine management
- Headlamp positioning
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- Typical applications ± 750 mA, 28 V
- Low RDS (On)Output, typically 0.5 Ω source and sink
- Automatic current decay mode detection/selection
- Mixed, fast, and slow current attenuation modes
- Synchronous rectification reduces power dissipation
- Internal overvoltage lockout (OVLO), undervoltage lockout (UVLO), and thermal shutdown circuitry
- Crossover current protection
- Short-circuit and open-circuit diagnostics
- High and low temperature warnings
- Stall detection function
- SPI-compatible or simple step and direction motion control
- Improved configurability with SPI-compatible serial interface