3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING AND POWER DMOS OUTPUTS

The A8909CLB is a three-phase brushless, back-EMF sensing, spindle-motor driver that integrates Analog bipolar, Analog and digital CMOS control functions, and DMOS power outputs on a single mono- lithic chip. It provides complete back-EMF sensing, commutation control, and drive of a spindle motor, and provides for an orderly spin- down in the event of supply-voltage removal. Energy for retracting the heads is regenerated from the spinning motor, while a controlled delay allows for a full retract before dynamic braking. The pulse-width modulation system and power DMOS outputs provide control of high currents with minimum power dissipation in the chip, and minimal average power supply currrent. UED PRODUCT REFERENCE ONL By Allegro MicroSystems, Inc.