AH2985 Smart Fan Motor Controller Diodes Inc. AH2985 Two-Phase Hall-Effect Smart Fan Motor Controller drives two-coil brushless direct current (BLDC) fans and motors. The AH2985 is optimized for low start-up voltage and includes a hall-effect sensor, dynamic offset correction, and two complementary open-drain output drivers with internal Zener diode protection. Diodes Inc. AH2985 controller has an operating voltage of 2.5V to 15V and average output current up to 500mA.