A89331 & A89331-1: Three Phase Sensorless Drivers

The A89331 three-phase motor drivers incorporate 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 family is designed to offer the features best suited for your needs.  The A89331 offers power-loss braking (PLB) while the A89331-1 offers an AC loss feature. 

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

Featured Applications:

Server and Datacenter Cooling Fans

• Closed Loop Speed Control
• Overvoltage Protection
• Power Loss Brake – A89331
• AC Loss – A89331-1
• 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