Allegro® MicroSystems, Inc. Introduces New DMOS Bipolar Stepper and DC Motor Driver
Efficient Motor Driver Offering High Current Rating and Very Small Package

Worcester, MA, December 22, 2006 — Allegro® MicroSystems, Inc. announces a new DMOS bipolar stepper and DC motor driver designed to drive one bipolar stepper motor at up to 1.2 A and one DC motor at up to 2.4 A. Capable of drive voltages up to 36 V, Allegro's A3989 includes a fixed off-time current regulator for each of the three full-bridges. The two stepper motor full-bridges feature Allegro’s patented mixed decay mode. This current decay control scheme results in reduced audible motor noise, increased step accuracy, and reduced power dissipation. The DC motor full-bridge current regulator operates in either fast or slow decay mode, determined by the MODE input.

Internal synchronous rectification control circuitry is provided to improve power dissipation during PWM operation. PHASE, ENABLE, and MODE inputs are provided for use in controlling the speed, torque, direction, and brake or coast functions of a DC motor. The stepper motor is controlled with PHASE, I0, and I1 inputs for full-, half-, or quarter-step operation. Protection features include thermal shutdown with hysteresis, undervoltage lockout (UVLO), and crossover current protection. Special power-up sequencing is not required.

Allegro’s A3989 is supplied in a lead (Pb) free 36L QFN package with exposed power tab for enhanced thermal dissipation. It has a 6 mm × 6 mm footprint and 0.90 mm nominal height.

About Allegro

Allegro MicroSystems, Inc. is a global leader in the development, manufacture, and marketing of high-performance power integrated circuits and integrated Hall-effect magnetic sensor ICs. Allegro’s innovative, system-level solutions serve high-growth applications within the automotive, computer/office automation, industrial, consumer, and communications markets. With more than 2,500 employees, Allegro is headquartered in Worcester, MA. Further information about Allegro can be found at www.allegromicro.com.

Editorial Contact:
Stephanie Fennelly
Director – Marketing Communications
Tel: (508) 854-5363
sfennelly@allegromicro.com

Allegro® MicroSystems, Inc. Introduces New DMOS Bipolar Stepper and DC Motor Driver Efficient Motor Driver Offering High Current Rating and Very Small Package

Allegro® MicroSystems, Inc. Introduces New DMOS Bipolar Stepper and DC Motor Driver
Efficient Motor Driver Offering High Current Rating and Very Small Package