A89331: Three Phase Sensorless Fan Driver


The A89331 three phase motor driver incorporates Sensorless sinusoidal drive to minimize vibration for high speed server fans. Sensorless control eliminates the requirement for hall sensors for server Fan applications.

A Flexible Closed loop speed control system is integrated into the IC. EEPROM is used to tailor the common functions of the fan speed curve to a specific application. This eliminates the requirement for a microprocessor based system and minimizes programming requirements.

The A89331 is available in a 28L 5x5 QFN with exposed power pad, (suffix ET), and a 20L TSSOP with exposed power pad (suffix LP).


Featured Applications:

Server and Datacenter Cooling Fans

Top Features

  • Closed Loop Speed Control
  • Overvoltage Protection
  • Power Loss Brake
  • Fault Mode Brake
  • Configurable RD or FG Output
  • Speed Curve Configuration via EEPROM
  • I2C Serial port
  • Sinusoidal modulation for Reduced Audible Noise and Low vibration
  • Sensorless (No Hall Sensors required)
  • Trapezoidal Drive Option for High Speed
  • Low RDSON Power MOSFETs – 3A capability
  • Minimal External Components
  • PWM Duty Cycle Speed Input
  • FG Speed Output
  • Lock Detection
  • Soft Start
  • Shorted Load Protection

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check Stock
APEK89331GLP-01-T DEMO BOARD -20°C to 85°C No -- New Contact your
local sales rep
Distributor Stock
A89331GETSR 28-lead QFN -40°C to 105°C -- View Data New Contact your
local sales rep
Distributor Stock
A89331GLPTR-T 20-lead TSSOP -40°C to 105°C Yes View Data New Contact your
local sales rep
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.


ET QFN with exposed pad 28 lead28 contact QFN with exposed thermal pad (suffix ET) 


20-Pin eTSSOP with exposed thermal pad LP Package20L TSSOP with exposed thermal pad (suffix LP)