A4988 Stepper Driver & Heatsink (Soldered Pins).

The A4988 is a popular stepper motor driver module used in many 3D printers, CNC machines, and other motion-control projects. It drives bipolar stepper motors with supply voltages up to 35 V and adjustable phase current up to 2 A (with proper cooling). With support for microstepping down to 1/16 step, it produces smoother motion and finer positioning—helping to reduce vibrations, layer shifts, and surface artifacts in printed parts.

Only two control signals—STEP and DIR—are needed from the controller board (e.g., RAMPS, SKR, Duet, etc.), making it compatible with most firmware such as Marlin, Klipper, and Repetier. Microstepping resolution is set via MS1–MS3 jumpers, while the maximum motor current is easily tuned by turning the onboard potentiometer.

For protection and reliability, the A4988 includes thermal shutdown, under-voltage lockout, and short-circuit protection. Logic power and motor power are kept separate, so it works with both 3.3 V and 5 V control electronics. Motor connections are made through the 1A/1B and 2A/2B terminals, which connect directly to the stepper motor coils.

In typical 3D printer setups, the A4988 is mounted in a socket on the control board, with a heatsink added for higher currents. Good cooling and proper current adjustment are essential for long-term reliability.

Key Features (3D Printer / CNC Use)

• Compatible with popular control boards (RAMPS, SKR, MKS, etc.)
• Works with firmware such as Marlin, Klipper, Repetier
• Simple 2-pin control (STEP, DIR)
• Adjustable motor current via onboard potentiometer
• Supports full-step, half-step, quarter-step, eighth-step, and sixteenth-step modes
• Separate motor power and logic power inputs (3.3 V or 5 V logic compatible)
• Thermal shutdown, under-voltage lockout, and short-circuit protection
• Compact plug-in module with heatsink compatibility
• Drop-in replacement for many Pololu-style driver slots

Specifications

• Motor type: Bipolar stepper motors (2-phase)
• Motor supply voltage (VMOT): 8 V – 35 V
• Logic voltage (VDD): 3.3 V or 5 V
• Max current per phase: 1 A without heatsink/fan, up to 2 A with cooling
• Microstepping: 1, 1/2, 1/4, 1/8, 1/16
• Current control method: Adjustable via reference voltage
• Protections: Over-temperature, short-to-ground, shorted load, under-voltage lockout
• Dimensions: ~15 × 20 mm (module)
• Operating temperature: -20°C to +85°C (with adequate cooling for high current use)

Documentation |  A4988 Stepper Driver