The A4979 is a flexibleMicrostepping motor driver, built-in converter, easy to operate. It uses a single-chip solution to drive bipolar stepper motors in full-step, half-step, quarter-, and sixteenth-step modes with operating voltages and currents up to 50 V and 1.5 A. The A4979 can be controlled by simple step and direction inputs or an SPI-compatible serial interface that can also be used to program a variety of integrated 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. In addition, phase ammeters can be programmed via a serial interface to create a unique microstep current distribution for specific applications, further improving motor performance.
Each phase current of the motor is 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.
The output is short-circuit protected. In addition, it features low load current and stall rotor detection. Chip-level protection includes: high and low temperature warnings, overtemperature shutdown, and undervoltage lockout. The A4979 is available in a 28-pin TSSOP power pack package with a heat sink (package type LP) on the outside. Lead-free package with 100% matte tin leadframe plating.
- Typical applications up to 1.5 A at 50 V
- Low RDS (On)Output, 0.5 Ω draw current, typical
- Automatic current decay mode detection/selection
- Hybrid, fast and slow current decay modes
- Low-power synchronous rectification
- Internal UVLO and thermal shutdown circuitry
- Crossover current protection
- Short-circuit and open-circuit load diagnostics
- High and low temperature warnings
- Stall detection function
- Compatible with SPI or simple step and direction motion control
- Highly configurable performance through an SPI-compatible serial interface