Allegro MicroSystems A5989GEVTR-T

Overview

A5989GEVTR-T from Allegro MicroSystems is a bipolar stepper and high-current DC motor driver IC in a 36-pin QFN package, supporting up to 1.6 A per phase for stepper motors and 3.2 A for DC motors at 40 V supply, with integrated PWM current regulation, mixed-decay control, and synchronous rectification for industrial motion control systems.

For engineers reviewing the A5989GEVTR-T datasheet, A5989GEVTR-T pinout, A5989GEVTR-T application, or A5989GEVTR-T equivalent, key selection criteria include dual-motor drive capability (stepper + DC), fixed off-time PWM with 30 µs off-time, VREF-based current programming, MODE-selectable decay mode, and thermal/UVLO/crossover-current protection.

Technical Context

The A5989GEVTR-T integrates three N-channel DMOS full-bridge drivers: two dedicated to bipolar stepper phases (Bridge 1 & 2) and one for DC motor control (Bridge 3), each regulated by independent fixed off-time PWM using external sense resistors and VREFx inputs. It employs Allegro's patented mixed-decay operation-30.1% fast decay followed by slow decay-for stepper windings, while DC decay mode is selected via the MODE pin.

Internal synchronous rectification reduces power dissipation during current decay; blanking times (1 µs for stepper, 3 µs for DC) suppress false overcurrent triggers from switching transients. Sleep mode (<1 µA quiescent current) disables charge pump and logic, and protection includes thermal shutdown (165°C typical), UVLO (7.6 V rising threshold), and latched overcurrent detection.

Key Specifications

Pinout & Package

Package: 36-pin QFN (6 mm × 6 mm × 0.9 mm), lead-free, with exposed thermal pad (PAD) for enhanced thermal performance and mandatory PCB soldering to ground plane.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bipolar stepper and high-current DC motor driver applications.

Compared with A5989GEVTR-T, A5988EVT offers identical thermal and packaging advantages but omits DC motor functionality, while TB6600HG delivers higher stepper current but demands external support circuitry and lacks integrated protection and low-power modes.

Availability

A5989GEVTR-T is available at Aetrix Electronics and suitable for industrial CNC positioning, medical infusion pumps, automotive HVAC actuators, and robotics joint control requiring stable component supply, long-lifecycle assurance, and traceable sourcing.

Supply support for A5989GEVTR-T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Allegro MicroSystems is a U.S.-based designer and manufacturer of high-performance magnetic sensing and power IC solutions, specializing in motion control, current sensing, and motor driver technologies.

The A5989 product line targets integrated motion systems requiring simultaneous stepper and DC motor control in space-constrained industrial and automotive applications, emphasizing thermal efficiency, noise reduction, and robust fault handling.

FAQ

What is the maximum continuous current rating for the stepper motor channels in the A5989GEVTR-T?

The A5989GEVTR-T supports up to 1.6 A continuous current per stepper motor phase (Bridges 1 and 2), limited by ambient temperature, PCB thermal design, and duty cycle. This rating assumes proper heatsinking via the exposed thermal pad and adherence to RθJA = 27 °C/W on a 4-layer board. Exceeding this current risks junction temperature exceeding 150°C and triggering thermal shutdown.

How does the A5989GEVTR-T implement mixed-decay operation, and why is it beneficial?

The A5989GEVTR-T implements mixed-decay by allocating 30.1% of its fixed 30 µs off-time to fast decay and the remaining 69.9% to slow decay per PWM cycle. This balances rapid current decay (reducing audible noise and improving step response) with low-loss recirculation (minimizing power dissipation). The result is quieter motor operation, tighter step accuracy, and cooler thermal performance compared to pure fast or slow decay modes.

Can the A5989GEVTR-T drive both a stepper motor and a DC motor simultaneously, and how are they controlled?

Yes, the A5989GEVTR-T drives one bipolar stepper motor (using Bridges 1 and 2) and one DC motor (using Bridge 3) concurrently. Stepper control uses PHASE1/PHASE2, I01/I11, I02/I12, and VREF1/VREF2 for step mode and current; DC control uses PHASE3, ENABLE, MODE, and VREF3 for direction, on/off, decay selection, and current limit. Both operate independently with shared VBB and ground resources.

What is the role of the VREF pins (VREF1, VREF2, VREF3) in the A5989GEVTR-T, and how do they affect current regulation?

The VREF1, VREF2, and VREF3 pins set the peak current trip point (ITripMax) for Bridges 1, 2, and 3 respectively, using the formula ITripMax = VREF / (3 × RS). Each accepts 0–1.5 V analog inputs, allowing independent, dynamic current scaling per motor channel. For example, applying 1.5 V to VREF1 with a 0.1 Ω sense resistor yields a 5 A theoretical limit, but the A5989GEVTR-T clamps actual continuous current to 1.6 A (stepper) or 3.2 A (DC) per its safe operating area.

Does the A5989GEVTR-T include built-in protection features, and what happens during an overcurrent event?

Yes, the A5989GEVTR-T includes undervoltage lockout (7.6 V rising threshold), thermal shutdown (165°C typical), crossover-current protection, and latched overcurrent protection. During an overcurrent event, the device disables all outputs and holds the fault state until either VBB is cycled or SLEEPn is asserted low - ensuring system safety without requiring external watchdog circuitry.