Part Number: A3987SLPTR-T

Manufacturer: Allegro MicroSystems

Description: IC MTR DRV BIPOLR 3-5.5V 24TSSOP

Shipped from: Shenzhen/HK Warehouse

Stock Available: Check with us

Technical Specifications of A3987SLPTR-T

Datasheet  A3987SLPTR-T datasheet
Category Integrated Circuits (ICs)
Family PMIC – Motor Drivers, Controllers
Manufacturer Allegro MicroSystems, LLC
Packaging Tape & Reel (TR)
Part Status Active
Motor Type – Stepper Bipolar
Motor Type – AC, DC
Function Driver – Fully Integrated, Control and Power Stage
Output Configuration Half Bridge (4)
Interface Step/Direction
Technology DMOS
Step Resolution 1, 1/2, 1/4, 1/16
Applications General Purpose
Current – Output 1.5A
Voltage – Supply 3 V ~ 5.5 V
Voltage – Load 8 V ~ 50 V
Operating Temperature -20°C ~ 150°C (TJ)
Mounting Type Surface Mount
Package / Case 24-TSSOP (0.173″, 4.40mm Width) Exposed Pad
Supplier Device Package 24-TSSOP-EP


The A3987SLPTR-T is a robust and flexible microstepping motor driver that was developed with the intention of making the operation of bipolar stepper motors more straightforward. This full motor driver has an integrated translator, making it simple to use even in situations where complex microprocessor control is either impossible or impractical to provide. In this in-depth tutorial, we will examine the A3987SLPTR-T microstepping motor driver, paying special attention to its most salient characteristics, advantages, and practical considerations.

Key Features and Benefits

● Microstepping Capabilities

Microstepping functionality is provided by the A3987SLPTR-T, and the step modes available on this device include full, half, quarter, and sixteenth steps. Because of this precision, motor control may be made more accurate and smoother, making it appropriate for situations in which accuracy is of the utmost importance.

● Voltage and Current Handling

The A3987SLPTR-T is able to manage a broad variety of stepper motors because to its remarkable output drive capacity of up to 50 volts and its current rating of 1.5 amps. This makes it useful for use in a variety of applications due to its adaptability.

● Built-In Translator

The A3987SLPTR-T is distinguished by its in-built translator, which is one of its most notable features. It does this by taking a single pulse on the step input and translating that into one microstep. This makes controlling the motor more simpler. This eliminates the need for complicated phase sequence tables and high-frequency control lines, making the A3987SLPTR-T both user-friendly and efficient.

● Current Decay Control

The A3987SLPTR-T comes equipped with a technology that allows for automatic identification and selection of current decay mode. This provides optimal motor performance by reducing audible motor noise, improving step accuracy, and minimizing power dissipation. These three factors contribute to motor performance. It has slow decay modes in addition to mixed decay modes, so that it may cater to the needs of a variety of applications.

● Safety Features

When it comes to the A3987SLPTR-T, safety is the number one concern. It offers protection against shorting to ground as well as protection against shorting loads, hence preventing any potential damage to the motor or driver in the event that a problem occurs.

● Low Power Mode

When the driver is not being used, the A3987SLPTR-T can enter a low-power mode known as SLEEP/RESET, which reduces the amount of power that is being consumed. This feature is helpful for designing systems that are efficient with energy and helps your stepper motor system last for a longer period of time.

Device Operation for the A3987SLPTR-T Microstepping Motor Driver

The microstepping motor driver known as the A3987SLPTR-T is a flexible component that was developed with the intention of making the control of bipolar stepper motors easier. We will delve into the operation of the device and highlight its most important features and functions as we proceed through this guide.

1. Microstepping Modes

The A3987SLPTR-T is capable of supporting a variety of microstepping modes, such as full, half, quarter, and sixteenth steps respectively. These modes allow for more precise control of the movement of the stepper motor, which results in motion that is both smoother and more accurate.

2. Full Bridge Control

The twin outputs of the driver are made with N-channel DMOS FETs, which are employed to produce full bridges. These complete bridges are essential for controlling the current supplied to the stepper motor windings.

3. Current Regulation

To manage the current flowing through the motor windings, the A3987SLPTR-T uses fixed off-time, pulse-width modulated (PWM) control circuitry. This guarantees that the motor’s current is kept within safe limits.

4. Setting Individual Step Currents

Each full bridge’s individual step currents are determined by a combination of factors:

  • This voltage establishes the basis for current regulation.
  • External Current Sense Resistor (RSENSEx): This resistor’s value assists in determining the current flowing through the motor windings.
  • Internal DAC (Digital-to-Analog Converter): The translator controls the output voltage of the internal DAC, allowing for exact control of the current.

5. Initial Home State

The translator sets the DACs and phase current polarity to the initial home state at power-up or after a reset. The term “home state” refers to a specified setup that ensures the motor driver’s safe and consistent operation.

6. Current Decay Modes

The A3987SLPTR-T offers two current decay modes:

  • Mixed Decay Mode: During power-up or reset, this mode is set as the default state. It optimizes current decay to balance motor performance.
  • Slow Decay Mode: This mode is activated automatically when the DAC level is more than or equal to the preceding level. Slow decay is used to improve microstepping performance by reducing current waveform distortion produced by the motor’s Back Electromotive Force (BEMF).

7. Microstep Resolution

The status of inputs MS1 and MS2 determines the microstep resolution. These inputs enable you to tailor the motor driver’s behavior to the specific needs of your application.

8. Input Protection

If logic inputs are pulled up to VDD, it is advisable to employ high-value pull-up resistors to safeguard the device against overvoltage events. This keeps excessive current from entering the logic inputs and maintains the driver’s dependability under a variety of operating scenarios.

9. Automatic Current Decay Selection

The A3987SLPTR-T streamlines microstepping performance by selecting the proper decay mode based on DAC output level changes. This dynamic adjustment aids in reducing distortion in the current waveform induced by the motor’s BEMF, resulting in improved motor performance.

Finally, the A3987SLPTR-T microstepping motor driver simplifies bipolar stepper motor control by providing a variety of microstepping modes, precision current management, and automatic decay mode selection. Its simple operation and adaptability to a variety of applications make it an excellent choice for projects requiring precise and efficient motor control.


In conclusion, the A3987SLPTR-T micro-stepping motor driver stands out as an exceptionally versatile and user-friendly solution for seamlessly controlling bipolar stepper motors. Its impressive array of features, including the built-in translator, micro-stepping capabilities, current regulation functions, and robust safety measures, make it an invaluable choice across a wide spectrum of applications.

To truly unlock the full potential of this remarkable motor driver, we invite you to consider joining forces with ICRFQ, a well-respected Chinese electronic component distributor. By reaching out to ICRFQ today, you can elevate your projects with the A3987SLPTR-T micro-stepping motor driver, enhance your communication systems, and ensure that your endeavors are backed by top-notch expertise and support

4.8/5 - (397 votes)
Kevin Chen