brief introduction
A4988 is a complete micro step motor driver with built-in converter for easy operation. The product can operate bipolar stepper motor in full, half, 1 / 4, 1 / 8 and 1 / 16 stepping mode, and the output driving performance can reach 35 V and 100 v ± 2 A。 The a4988 includes a fixed off time current regulator that can operate in slow or mixed decay modes. The converter is the key to the easy implementation of a4988. As long as a pulse is input in the "step" input, the motor can be driven to generate micro step. There is no need to program phase sequence table, high frequency control line or complex interface. The a4988 interface is very suitable for complex applications where microprocessors are unavailable or overloaded.
In micro step operation, the chopper control in a4988 can automatically select the current attenuation mode (slow or mixed). In the mixed decay mode, the device is initially set to decay rapidly in part of the fixed down time, and then slowly in the rest of the down time. The hybrid attenuation current control scheme can reduce audible motor noise, increase stepping accuracy and reduce power consumption. An internal synchronous rectification control circuit is provided to improve the power consumption during pulse width modulation (PWM) operation. Internal circuit protection includes: thermal shutdown with hysteresis, undervoltage locking (UVLO) and cross current protection. No special power on sequencing is required.
A4988 is in a surface mount QFN package (ES) with a size of 5 mm × 5 mm, the nominal overall package height is 0.90 mm, with exposed heat dissipation plate to enhance the heat dissipation function. The package is a lead-free package (suffix – T) with a 100 100% tin plated pin frame.
Functions and advantages
Low RDS (on) output
Automatic current decay mode detection / selection
Mixing and slow current decay mode
Research on low power dissipation synchronous rectifier
Internal UVLO
Cross current protection
3.3 and 5 V compatible logic power supply
Thermal shutdown circuit
Ground short circuit protection
Load short circuit protection
Five optional stepping modes: full, 1 / 2, 1 / 4, 1 / 8 and 1 / 16
