A3918 DC Motor Driver

By Allegro MicroSystems, LLC 57

A3918 DC Motor Driver

Designed for pulse width modulated (PWM) control of a low voltage DC motor, Allegro MicroSystems' A3918 is capable of output currents up to 1.5 A and operating voltages from 2.5 to 9 V. The A3918 has an internal fixed off-time PWM timer that sets a peak current based on the selection of a current sense resistor. An overcurrent output flag is provided that notifies the user when the current in the motor winding reaches the peak current determined by the sense resistor. The fault output flags the user when PWM is active but does not affect driver operation. The A3918 is provided in a 16-contact, 3 mm × 3 mm, 0.75 mm nominal overall height QFN, with exposed pad for enhanced thermal dissipation. It is lead (Pb) free with 100% matte tin lead-frame plating.

  • Two stage charge pump provides gate drive down to 2.5 V
  • Internal PWM current control set by selection of current sense resistor
  • Synchronous rectification for reduced power dissipation
  • Peak current output flag notifies user when PWM current limit is reached
  • Undervoltage lockout protects the user from power-up sequencing
  • Small package
  • Brake mode for DC motor
  • Sleep function provides a low standby current for battery operated applications
  • Crossover-current protection
  • Thermal shutdown
  • Digital still cameras (DSC)
  • Cell phone cameras
  • USB powered devices
  • Battery powered devices
  • Electric toothbrush
  • Robotics
  • Imaging focus or zoom
  • Valve control for gas shut-off
  • Infusion pumps
  • Agitators

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