1、Low RDS (on) output. 2、Automatic current decay mode detection / selection. 3、Mixing and slow current decay mode. 4、For low power dissipation synchronous rectification. 5、Internal UVLO. The A4988 is a complete microstepping motor driver with built-in translator for easy operation. This product uses full, half, 1/4, 1/8 and 1/16 stepping modes, bipolar stepper motor, output drive capability up to 35 V and ±2A. The A4988 includes a fixed shutdown current regulator with the regulator in a slow or mixed decay mode. The A4988 converter is the key to easy implementation. Just enter a pulse of "step" input to drive the motor a microstep. There are no phase sequence tables, high frequency control lines or complex programming interfaces. The A4988 interface is ideal for complex microprocessors that are either unavailable or overburdened. In microstep operation, the A4988 chopping control automatically selects the current decay mode (slow or mixed). In mixed decay mode, the device is initially set to a fixed downtime at some fast decay and then the remaining slow decay downtime. Hybrid attenuation current control scheme reduces audible motor noise, improves step accuracy, and reduces power consumption. An internal synchronous rectification control circuit is provided to improve the power consumption of pulse width modulation (PWM) operation. Internal circuit protection includes: thermal shutdown with hysteresis, undervoltage lockout (UVLO) and cross current protection. Special power sequencing. The A4988 surface mount QFN package (ES) measures 5 mm x 5 mm and has a nominal total package height of 0.90 mm with an exposed pad for enhanced heat dissipation. The package is Pb (suffix-T) with 100% matte leadframe plating. Features: 1. Low RDS (on) output. 2. Automatic current decay mode detection / selection. 3. Mixing and slow current decay mode. 4. For low power dissipation synchronous rectification. 5. Internal UVLO. 6. Cross current protection. Specifications: Material: Metal Model: Stepper Motor Drive Module Size: Approx. 2*1.5*1cm/0.79*0.59*0.39in Package List: 5 * Module 5 * Heat dissipation Pad