A3955SLB-T

Overview

The A3955SLB-T is a full-bridge PWM microstepping motor driver designed for bipolar stepper motors. It supports continuous output currents up to ±1.5 A and operates with voltages up to 50 V. The device integrates an internal three-bit nonlinear digital-to-analog converter (DAC) for current control, enabling full-, half-, quarter-, or eighth-step microstepping modes. Key electrical parameters include a 50 V output voltage rating and integrated transient-suppression diodes.

Feature Summary

• Integrates internal pulse width modulated (PWM) current control combined with a three-bit nonlinear DAC for precise microstepping operation.
• Provides fast, mixed fast/slow, and slow current-decay modes to optimize motor performance.
• Includes internal protection features such as thermal shutdown, crossover-current protection, and under-voltage lockout (UVLO).

Applications

• Microstepping drive for bipolar stepper motors
• General-purpose motor control systems requiring high step resolution
• Applications minimizing torque variations and resonance problems at low speeds

Procurement Notes

Verify the specific suffix against official Allegro MicroSystems documentation to confirm package type and tape-and-reel specifications. Ensure the component matches the required operating temperature range and voltage ratings for your application. Cross-reference the manufacturer part number with authorized distributors to avoid counterfeit components.

Selection Notes

Select this driver when bipolar stepper motor applications require integrated microstepping capabilities without external logic. The built-in nonlinear DAC reduces control line complexity compared to linear DAC solutions. Consider the ±1.5 A current rating and 50 V voltage tolerance to ensure compatibility with the target motor's power requirements.

Part Context

The A3955 belongs to Allegro Microsystems' family of DMOS full-bridge microstepping drivers. It is engineered to replace discrete MOSFET bridge designs by integrating control logic, power stages, and protection circuits into a single package. This integration simplifies PCB layout and reduces system component count for stepper motor applications.

Replacement Considerations

The A3957 is a documented similar full-bridge PWM microstepping motor driver from the same manufacturer. Verify pin compatibility and current/voltage ratings before substitution.