A4975 Microstepping Drivers

By Allegro MicroSystems, LLC 121

A4975 Microstepping Drivers

Allegro's A4975 is designed to drive one winding of a bipolar stepper motor in a microstepping mode. The outputs are rated for continuous output currents to ±1.5 A and operating voltages to 50 V. Internal pulse width modulated (PWM) current control combined with an internal three-bit nonlinear digital-to-analog converter allows the motor current to be controlled in full-, half-, quarter-, or eighth-step (microstepping) modes. Nonlinear increments minimize the number of control lines necessary for microstepping. Microstepping provides increased step resolution, and reduces torque variations and resonance problems at low speed.

The A4975 is supplied in a choice of two power packages, a 16-pin dual-in-line plastic package with copper heat-sink tabs (suffix B), and a 16-lead plastic SOIC with internally fused pins (suffix LB). For both package styles, the thermally enhanced pins are at ground potential and need no electrical isolation. Both packages are lead (Pb) free, with leadframe plating 100% matte tin.

  • ±1.5 A continuous output current
  • 50 V output voltage rating
  • Internal PWM current control
  • 3-bit nonlinear DAC
  • Fast, mixed fast/slow, and slow current-decay modes
  • Internal thermal shutdown circuitry
  • Crossover-current and UVLO protection

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