A4988 is a complete microstepping motor driver with built-in translator for easy operation. This product is available in full, half, 1/4, 1/8 and 1/16 step modes operate bipolar stepper motors, output drive capacity of up to 35 V and ± 2 A. A4988 includes a fixed off-time current regulator, the regulator in slow or mixed decay modes. A4988 converter is the key to the easy implementation. As long as the "step" input inputting one pulse drives the motor one microstep. There are no phase sequence tables, high frequency control lines, or complex interfaces to program. A4988 interface is very suitable for complex microprocessor is unavailable or is overburdened.
     In the micro-step operation, A4988 chopping control inside automatically selects the current decay mode (Slow or Mixed). In mixed decay mode, the device is initially set to a fixed downtime in some fast decay, then the rest of the slow decay downtime. Mixed decay current control scheme results in reduced audible motor noise, increased step accuracy, and reduced power consumption. Internal synchronous rectification control circuitry is provided to improve the pulse-width modulation (PWM) operation power consumption. Internal circuit protection includes: thermal shutdown with hysteresis, undervoltage lockout (UVLO), and crossover-current protection. Special power sequencing.

A4988 surface mount QFN package (ES), a size of 5 mm × 5 mm, nominal overall package height of 0.90 mm, with an exposed pad for enhanced thermal dissipation. This package is Pb (suffix-T), with 100% matte tin leadframe plating.

Features and Benefits
· Low RDS (On) Output
· Automatic current decay mode detection / selection
· Mix with slow current decay modes
· Synchronous rectification for low power dissipation
· Internal UVLO
· Cross-current protection
· 3.3 and 5 V compatible logic supply
· Thermal shutdown circuitry
· Ground fault protection
· Load short-circuit protection
· Optional step five modes: full, 1/2, 1/4, 1/8 and 1/16