A3989 Datasheet | Allegro MicroSystems

Bipolar Stepper and High Current DC Motor Driver Features AND BENEFITS - 36 V output rating - 2.4 A DC motor driver - 1.2 A bipolar stepper driver - Synchronous rectification - Internal undervoltage lockout (UVLO) - Thermal shutdown circuitry - Crossover-current protection - Very thin profile QFN package Package: 36 pin QFN with exposed thermal pad 0.90 mm nominal height (suffix EV) Not to scale DESCRIPTION The A3989 is designed operate at voltages up to 36 V while driving one bipolar stepper motor at currents up to 1.2A, and one DC motor at currents up to 2.4 A. The A3989 includes a fixed off-time pulsewidth modulation (PWM) regulator for current control. The stepper motor driver Features dual 2-bit nonlinear DACs (digital-to-analog converters) that enable control in full, half, and quarter steps. The DC motor is controlled using standard PHASE and ENABLE signals. Fast or slow current decay is selected via the MODE pin. The PWM current regulator uses the Allegro™ patented mixed decay mode for reduced audible motor noise, increased step accuracy, and reduced power dissipation. Internal synchronous rectification control circuitry is provided to improve power dissipation during PWM operation. Protection Features include thermal shutdown with hysteresis, undervoltage lockout (UVLO) and crossover current protection. Special power up sequencing is not required. The A3989 is supplied in a leadless 6 mm × 6 mm × 0.9 mm, 36-pin QFN package with exposed power tab for enhanced thermal performance. The package is lead (Pb) free, with 100% matte tin leadframe plating. Microcontroller or Controller Logic A3989DS, Rev. 6 MCO-0000354 0.1 µF 50 V CP1 VDD 0.1 µF 50 V CP2 VCP 100 µF 50 V VBB VBB OUT1A PHASE1 I01 I11 PHASE2 I02...