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The A4988 is a complete microstepping motor driver with built-in converter, easy to operate. The products can be in full, half, 1/4, 1/8 and 1/16 step mode of operation bipolar stepper motor, output drive performance up to 35 V and ± 2 A. A4988 includes a fixed off time current regulator, the regulator can be in slow or mixed decay mode. The converter is the key to the easy implementation of the A4988. As long as the input of a pulse in the "step" in the input can be driven motor, microstep. There are no phase sequence tables, high frequency control interface programming or complex. The application of A4988 interface is very suitable for complex microprocessor is not available or overload.
In the stepping operation, the chopping control in the A4988 automatically selects the current decay mode (slow or mixed). In mixed decay mode, the device is initially set to rapid degradation in the portion of the fixed off time, then the attenuation in the stop time slow the rest. Mixed decay current control scheme can reduce the audible motor noise, increased step accuracy, and reduced power consumption. Provide internal synchronous rectification control circuitry, in order to improve the pulse width modulation (PWM) power consumption during operation. Internal circuit protection includes: thermal shutdown with hysteresis, undervoltage lockout (UVLO) and crossover current protection. Don't need special power up sequencing.
A4988 uses surface mount QFN package (ES), the size is 5 mm × 5 mm, nominal overall package height is 0.90 mm, with an exposed thermal pad to enhance heat dissipation function. The package is a lead-free package (suffix - T), with 100% matte tin leadframe plating.
Function and advantages
Low RDS (open) output
Automatic current decay mode detection / choice
Mixed with slow current decay mode
The low power dissipation of synchronous rectifier
Crossover current protection
3.3 and 5 V compatible logic supply
Thermal shutdown circuit
Ground fault protection
Loading and short circuit protection
The optional five step mode: full, 1/2, 1/4, 1/8 and 1/16