A3938SEQ

Overview

The A3938SEQ is a three-phase brushless DC (BLDC) motor pre-driver manufactured by Allegro MicroSystems. It provides direct gate drive for an all N-channel power MOSFET three-phase bridge. The device integrates three Hall element inputs for commutation control, a sequencer, fixed off-time PWM current control, and locked-rotor detection. It operates with a supply voltage range of 18V to 50V and supports parallel and PWM interfaces. The component is housed in a 32-PLCC package with dimensions of 11.43x13.97 mm and functions within a temperature range of -20°C to 85°C.

Feature Summary

• Integrates a commutation sequencer and Hall element inputs for precise BLDC motor control
• Provides direct high-current gate drive for external N-channel power MOSFETs
• Includes internal circuit protection features such as thermal shutdown and undervoltage lockout

Applications

• Three-phase brushless DC motor control systems
• Industrial automation equipment requiring precise motor direction management
• Appliances utilizing BLDC motors with external power stages

Procurement Notes

Verify the specific suffix 'SEQ' corresponds to the 32-PLCC package variant when sourcing. Confirm RoHS compliance status as documentation indicates non-compliance for this series. Check component availability status as listings indicate potential discontinuation. Ensure compatibility with external MOSFET capabilities since output current scales with external components.

Selection Notes

Select this component for applications requiring integrated commutation logic without a microcontroller. It is suitable for designs using external N-channel MOSFETs to handle higher power levels. Consider the 32-PLCC package constraints for PCB layout. Verify that the required operating voltage falls within the 18V to 50V range. Evaluate if the fixed off-time PWM control meets the specific current regulation needs of the motor.

Part Context

The A3938SEQ belongs to the A3938 family of three-phase BLDC pre-drivers from Allegro MicroSystems. This family is designed to simplify motor control by integrating sequencing and protection. Other variants in the series include different package options like QSOP and TSSOP, offering flexibility for various board space requirements while maintaining similar functional core specifications.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.