A3955SLBTR

Overview

The A3955SLBTR-T is a full-bridge PWM microstepping motor driver designed for bipolar stepper motors. It supports continuous output currents of ±1.5 A and operating voltages up to 50 V. The device integrates an internal three-bit nonlinear digital-to-analog converter (DAC) for current control in full, half, quarter, or eighth-step modes. Key electrical parameters include a supply voltage range of 4.5 V to 5.5 V and a load voltage rating of 20 V to 50 V. It operates within a temperature range of -20°C to +85°C and is housed in a 16-SOIC package.

Feature Summary

• Integrates internal pulse width modulated (PWM) current control with a three-bit nonlinear DAC for precise microstepping resolution.
• Provides fast, mixed fast/slow, and slow current-decay modes to optimize motor performance.
• Includes internal transient-suppression diodes, thermal shutdown circuitry, crossover-current protection, and UVLO.

Applications

• Bipolar stepper motor drives requiring microstepping capabilities
• Printers and scanners
• Office automation equipment

Procurement Notes

Verify the exact suffix against official Allegro MicroSystems documentation, as 'A3955SLBTR' may refer to the reel variant 'A3955SLBTR-T'. Confirm RoHS compliance status and moisture sensitivity level (MSL) requirements for your assembly process. Ensure the ordering part number matches the specific package and tape-and-reel specifications listed in the manufacturer's datasheet to avoid compatibility issues.

Selection Notes

Select this component when driving bipolar stepper motors with peak currents up to 1.5 A and voltages up to 50 V. It is suitable for applications requiring integrated microstepping control without external logic. Consider the 16-SOIC package size and operating temperature range (-20°C to +85°C) for board layout and environmental constraints. Verify that the 4.5 V to 5.5 V supply voltage aligns with your system power rails.

Part Context

The A3955 belongs to Allegro MicroSystems' family of full-bridge microstepping motor drivers. It is designed to simplify the drive of bipolar stepper motors by integrating control logic, power stages, and protection features into a single IC. This integration reduces the component count and board space required compared to discrete solutions.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided source material. Consult Allegro MicroSystems for potential obsolescence notices or recommended upgrades if this part is discontinued.

FAQ

What microstepping resolutions does the A3955 support?

The A3955 supports full, half, quarter, and eighth-step microstepping modes via its internal three-bit nonlinear DAC.

What is the maximum continuous output current rating?

The outputs are rated for continuous output currents of ±1.5 A.