Allegro MicroSystems A2919SLBTR-T

Overview

A2919SLBTR-T from Allegro MicroSystems is a dual full-bridge PWM motor driver IC designed to control two DC motors bidirectionally or drive both windings of a bipolar stepper motor. It sustains 45 V motor supply, delivers 750 mA continuous output current per bridge, and features internal PWM current control with selectable 0%/41%/67%/100% current limits via logic inputs I0/I1 - used in industrial motion control systems requiring precise microstepping.

For engineers reviewing the A2919SLBTR-T datasheet, A2919SLBTR-T pinout, A2919SLBTR-T application, or A2919SLBTR-T equivalent, key selection criteria include its 24-pin SOICW package with exposed thermal tabs, integrated clamp/flyback diodes, fixed off-time PWM (46 μs typ.), thermal shutdown at 170°C, and support for half- and quarter-step stepper operation without external sequencing.

Technical Context

The A2919SLBTR-T implements two independent H-bridge channels, each with PHASE-controlled direction and I0/I1-selectable current limit thresholds (VREF/10RS, VREF/15RS, VREF/24.4RS). Its monostable-based PWM uses external RT/CT components (e.g., 56 kΩ/820 pF) to set fixed off-time (46 μs), enabling current chopping above audible range while avoiding crossover currents via 2 μs internal dead time.

Each bridge integrates source/sink drivers optimized for low saturation voltage (<1.8 V total at 500 mA), ground-clamp and flyback diodes for inductive transient protection, and thermal shutdown that disables outputs at 170°C junction temperature - re-enabling at 145°C. No special power-up sequencing is required.

Key Specifications

Pinout & Package

Package: 24-pin SOICW (suffix LB) with exposed thermal tab - batwing construction enhances thermal dissipation (θ_JA = 55°C/W), enabling sustained 750 mA operation per bridge with minimal PCB copper area.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual full-bridge motor driver applications.

Compared with TB6600HG and DRV8825, the A2919SLBTR-T uniquely combines dual independent PWM bridges with integrated diodes, fixed off-time regulation, and a thermally enhanced SOICW package - making it optimal for industrial stepper systems prioritizing reliability, simplicity, and thermal stability over ultra-fine microstepping or extreme current capability.

Availability

A2919SLBTR-T is available at Aetrix Electronics and suitable for industrial motion control, automated test equipment, medical lab automation, and print head motion control requiring stable component supply despite its Last Time Buy status.

Supply support for A2919SLBTR-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 Hall-effect sensors and power ICs, founded in 1989 and headquartered in Worcester, Massachusetts.

The A2919 product line was developed specifically for cost-sensitive, thermally demanding industrial stepper and dual-DC motor control applications - emphasizing integration, thermal resilience, and simplified microcontroller interfacing.

FAQ

What is the maximum continuous current per bridge for the A2919SLBTR-T?

The A2919SLBTR-T supports ±750 mA continuous output current per bridge under conditions of TA ≤ 85°C, adequate PCB copper area, and proper decoupling. This rating assumes use of the exposed thermal tab in the 24-pin SOICW package and accounts for internal saturation voltage losses. Peak current is ±1.0 A for pulses ≤20 μs, but sustained operation above 750 mA risks thermal shutdown activation.

Does the A2919SLBTR-T require external flyback diodes?

No, the A2919SLBTR-T integrates clamp and flyback diodes for both bridges - eliminating the need for eight external diodes. These internal diodes protect against inductive transients generated by stepper windings or DC motor back-EMF, reducing bill-of-materials cost and PCB footprint. The device relies solely on its internal protection structure when operated within absolute maximum ratings.

How does the A2919SLBTR-T implement microstepping without a microcontroller PWM signal?

The A2919SLBTR-T uses an internal monostable multivibrator and comparator to generate fixed off-time PWM autonomously. By setting VREF and RS, the device self-regulates peak current; I0/I1 logic inputs then scale that trip point to 100%/67%/41%/0%. This enables half- and quarter-step sequences using only direction (PHASE) and digital current select signals - no external PWM generation or high-frequency timing resources are required from the host MCU.

What is the purpose of the RC1 and RC2 pins on the A2919SLBTR-T?

RC1 and RC2 pins connect to external RC timing networks (RT and CT) that set the fixed off-time for each bridge's PWM cycle. For example, with RT = 56 kΩ and CT = 820 pF, the off-time is 46 μs - ensuring current regulation remains above audible frequencies. These pins allow independent tuning of decay time per bridge, critical for optimizing torque consistency and minimizing resonance in stepper applications.

Is the A2919SLBTR-T still available for new designs?

The A2919SLBTR-T was classified as Last Time Buy effective October 29, 2010, and is restricted to existing customer applications. Aetrix Electronics maintains limited legacy inventory for continuity support, but new designs should evaluate alternatives like the TB6600HG or DRV8825. Engineering samples are no longer available, and Allegro does not recommend A2919SLBTR-T for prototyping or production starts after 2010.