Allegro MicroSystems A4988 DMOS Microstepping Driver
Allegro MicroSystems A4988 DMOS Microstepping Driver features a built-in translator for easy operation and is designed to operate bipolar stepper motors in full-, half-, quarter-, eighth-, and sixteenth-step modes. This driver has a fixed off-time current regulator that can operate in slow or mixed decay modes. Easy implementation is accomplished with the translator, and simply inputting one pulse on the STEP input drives the motor one microstep. There are no phase sequence tables, complex interfaces, or high-frequency control lines to program, making this driver an ideal fit for applications where complex microprocessors are unavailable or overburdened.
During stepping operation, the chopping control in the A4988 selects the current decay mode automatically: slow or mixed. When in mixed decay mode, the Allegro MicroSystems A4988 is set initially to a fast decay for a proportion of the fixed off-time, then to a slow decay for the remainder of the off-time. Mixed decay current control results in increased step accuracy, reduced audible motor noise, and reduced power dissipation. The provided internal synchronous rectification control circuitry improves power dissipation during PWM operation, and the internal circuit protection includes undervoltage lockout (UVLO), crossover-current protection, and thermal shutdown with hysteresis.
Features
- Five selectable step modes: full, half, quarter, eighth, and sixteenth
- Low RDS(ON) outputs
- Automatic current decay mode detection/selection
- Mixed and slow current decay modes
- Synchronous rectification for low-power dissipation
- Internal UVLO
- Crossover-current protection
- Thermal shutdown circuitry
- Short-to-ground protection
- Shorted load protection
Specifications
- 3.3V and 5V compatible logic supply
- 35V load supply voltage
- ±2A output current
- -20°C to +85°C temperature range
- 5mm x 5mm, 28-contact QFN package with exposed thermal pad
TYPICAL APPLICATION DIAGRAM
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