A4988 Stepper Motor Driver Carrier with Voltage Regulators

The A4988 stepper motor driver carrier with voltage regulators is
a breakout board for Allegro’s easy-to-use A4988 microstepping bipolar stepper motor driver.
The board has two voltage regulators (5 V and 3.3 V), eliminating the need for separate logic and motor supplies.
The driver features adjustable current limiting, overcurrent protection, and five different microstep resolutions.
It operates from 8 – 35 V and can deliver up to 2 A per coil with sufficient additional cooling
(it can deliver up to approximately 1 A per phase without a heat sink or forced air flow).
 

This product is a carrier board or breakout board for Allegro’s A4988 DMOS Microstepping
Driver with Translator and Overcurrent Protection; we therefore recommend careful reading of the A4988 datasheet
(380k pdf) before using this product.
This stepper motor driver lets you control one bipolar stepper motor at up to 2 A output current per coil
(see the Power Dissipation Considerations section below for more information).
 

מאפיינים

• Simple step and direction control interface
• Five different step resolutions: full-step, half-step, quarter-step, eighth-step, and sixteenth-step
• Adjustable current control lets you set the maximum current output with a potentiometer, which lets you use voltages above your stepper motor’s rated voltage to achieve higher step rates
• Intelligent chopping control that automatically selects the correct current decay mode (fast decay or slow decay)
• Over-temperature thermal shutdown, under-voltage lockout, and crossover-current protection
• Short-to-ground and shorted-load protection

This carrier has reverse power protection on the main power input and
built-in 5 V and 3.3 V voltage regulators that eliminate the need for separate logic
and motor supplies and let you control the driver with microcontrollers powered at 5 V or 3.3 V.
We also sell a smaller, higher-performace version of the A4988 carrier without voltage regulators.

Like nearly all our other carrier boards, this product ships with all surface-mount
components—including the A4988 driver IC—installed as shown in the product picture.
 

Power connections

The driver requires a logic supply voltage (3 – 5.5 V) to be connected across the
VDD and GND pins and a motor supply voltage of (8 – 35 V) to be connected across VMOT and GND.
The logic voltage can be supplied from an external source, such as that
powering the logic of the rest of the system, or by jumpering the output of the 5 V or 3.3 V voltage regulator outputs to VDD.
There are also surface-mount pads that allow VDD selection to be made by making a solder bridge across the appropriate pads.
Note that the driver’s regulators can also be used to power other electronics in the system, such as the controlling MCU.

The motor power supply should be capable of delivering the expected currents for the stepper motors being used (peaks up to 4 A).
 

The resolution (step size) selector inputs (MS1, MS2, and MS3) enable selection from the five step resolutions according to the table below. MS1 and MS3 have internal 100kΩ pull-down resistors and MS2 has an internal 50kΩ pull-down resistor, so leaving these three microstep selection pins disconnected results in full-step mode. For the microstep modes to function correctly, the current limit must be set low enough (see below) so that current limiting gets engaged. Otherwise, the intermediate current levels will not be correctly maintained, and the motor will skip microsteps.

Dimensions

General specifications