A3972SB

Overview

The A3972SB is a dual DMOS full-bridge microstepping PWM 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 features low RDS(on) DMOS output drivers, optimized microstepping via 6-bit linear DACs, and programmable mixed, fast, and slow current-decay modes controlled via a serial interface. It includes a 4 MHz internal oscillator for digital timing, synchronous rectification for low power dissipation, and internal UVLO and thermal shutdown circuitry. Inputs are compatible with 3.3 or 5 V control signals, and it offers sleep and idle modes.

Feature Summary

• Integrated dual DMOS full-bridge architecture for bipolar microstepping stepper motor control
• Serial interface controls chip functions including programmable mixed, fast, and slow current-decay modes
• Synchronous rectification reduces power dissipation by eliminating most external clamp diodes
• Built-in protection mechanisms include crossover-current protection, thermal shutdown, and internal UVLO

Applications

• Pulse-width modulated (PWM) current control of bipolar microstepping stepper motors
• Systems requiring precise positioning with integrated control and power stages
• Applications utilizing 3.3 V or 5 V logic level control signals

Procurement Notes

Verify the specific suffix 'SB' indicates the 24-pin DIP package configuration. Confirm RoHS compliance status as some listings indicate non-compliance. Check component lifecycle status, as this part may be obsolete. Ensure the design accommodates the required thermal management for the DIP package given the continuous current ratings.

Selection Notes

Select this component when a fully integrated solution for bipolar stepper motors is required. It is suitable for designs needing ±1.5 A continuous current and up to 50 V supply voltage. Consider the serial interface requirement for configuring decay modes and microstepping resolution. Evaluate thermal performance requirements against the 24-DIP package capabilities.

Part Context

The A3972SB belongs to Allegro MicroSystems' A3972 family of dual DMOS full-bridge microstepping PWM motor drivers. It is functionally similar to the A3992 series but distinguished by its specific package and interface configuration. This component integrates both the controller and power stages, simplifying the design for stepper motor applications compared to discrete solutions.

Replacement Considerations

Public confirmed substitute part numbers include A3972SL and A3992. Verify pinout compatibility and electrical specifications before substitution.