A3955SB-T

Overview

The A3955SB-T is a full-bridge PWM microstepping motor driver designed for bipolar stepper motors. It features a 16-pin PowerDIP package with an integrated copper heat slug. The device supports a maximum supply voltage of 50 V and delivers a continuous output current of ±1.5 A per phase. It incorporates internal pulse-width modulation current control combined with a three-bit nonlinear digital-to-analog converter to enable full, half, quarter, or eighth-step microstepping modes. Operating temperatures range from -20°C to +150°C junction temperature.

Feature Summary

• Integrates internal PWM current control with a three-bit nonlinear DAC for precise microstepping resolution
• Supports selectable slow, fast, and mixed current decay modes for optimized motor performance
• Includes built-in thermal shutdown, cross-current protection, and transient suppression diodes

Applications

• Bipolar stepper motor drive systems requiring microstepping control
• Printers and scanners utilizing precision motion stages
• Automated valve actuators in industrial equipment
• Medical instrumentation requiring smooth low-speed operation

Procurement Notes

Verify the specific suffix 'T' indicates tape-and-reel packaging when ordering. Confirm the 'B' suffix corresponds to the 16-pin DIP package with copper heat slug as specified. Ensure compatibility with existing PCB footprints for PowerDIP components. Check for RoHS compliance status if required by project specifications. Validate that the load voltage does not exceed the 50 V rating during peak transients.

Selection Notes

Select this component for applications requiring integrated control and power stages for bipolar stepper motors. The device eliminates external logic requirements through its parallel interface and internal DAC. Consider the thermal performance of the DIP package with heat slug for high-current operations. Evaluate the need for microstepping capabilities to reduce resonance and improve resolution compared to standard step drivers.

Part Context

This part belongs to the Allegro A3955 family of microstepping motor drivers. It is specifically the DIP package variant (suffix B) with reel packaging (suffix T). The family is designed to simplify bipolar stepper motor control by integrating PWM regulation and current sensing interfaces. It serves as a complete solution for driving single windings of bipolar stepper motors in various automation environments.

Replacement Considerations

The A3955SLBTR-T is the surface-mount SOIC equivalent within the same product family. Verify pinout compatibility and thermal dissipation requirements when switching between DIP and SOIC packages. Ensure the replacement supports the same 50 V and 1.5 A ratings. Confirm that the microstepping resolution options remain consistent across package variants.