By Allegro MicroSystems, LLC 45
Allegro's A5988 is a quad, DMOS, full-bridge driver capable of driving up to two stepper motors or four DC motors. Each full-bridge output is rated up to 1.6 A and 40 V. The A5988 includes fixed, off-time, pulse width modulation (PWM) current regulators along with 2-bit, nonlinear digital-to-analog converters (DACs) that allow stepper motors to be controlled in full, half, and quarter-step modes and DC motors in forward, reverse, and coast modes. The PWM current regulator uses Allegro's 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, and low-current sleep mode is included to improve efficiency.
Protection features include thermal shutdown with hysteresis, undervoltage lockout (UVLO), and crossover current and overcurrent protection. Special power-up sequencing is not required.
The A5988 is supplied in two packages, EV and JP, with exposed power tabs for enhanced thermal performance. The EV is a 6 mm x 6 mm, 36-pin QFN package with a nominal overall package height of 0.90 mm. The JP is 7 mm x 7 mm and 48-lead. Both packages are lead- (Pb) free with 100% matte tin lead-frame plating.
The A5988 is a drop-in replacement to the Allegro A3988 with key features to improve reliability and efficiency. These features are described in the Pitch Pack presentation and include:
