ALLEGRO A5931KLPTR-T

The A5931 three-phase motor driver IC 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 A5931 is available in a 24-contact 4 mm×4 mm QFI N with exposed thermal pad (suffix ES), and a 16-lead TSSOP with exposed thermal pad (suffix LP). These packages are lead (Pb) free, with 100% matte-tin leadframe plating. The A5931 targets high-speed fan applications to meet the objectives of minimal vibration, high efficiency, and ability to customize the IC to the speed control specification. In typical systems, an MCU is required to meet each application specification. The A5931 integrates the basic closed-loop speed control function, thus allowing elimination of the cost, PCB space, and programming requirements of a custom MCU. Protection features include lock detection with restart, overcurrent limit, motor output short circuit, supply undervoltage monitor, and thermal shutdown. Standby mode can be achieved by holding SPD pin low for longer than the programmed lock off-time. In specific speed curve options, the motor will never turn off, if speed is set to run at a minimum value with 0% duty cycle applied. In this type of configuration, standby mode is not available. FG. Open-drain output, represents the speed of the motor for normal operation. Additionally, the FG pin serves as the data line, (SDA) for I2C communication. RD. Open-drain output, logic high indicates a rotor fault condition as defined by EEPROM variables. RD function can be disabled via EEPROM. When function is disabled, RD pin goes high to indicate end of open-loop starting sequence. SPD. Speed Demand input pin. Choice of analog voltage control or PWM duty control is determined by EEPROM selection. CTAP. This analog input is an optional connection for motor common (Wye motors). It is required to insert a 2 kΩ resistor in series with the pin.

• AEC-Q100 qualified (K version)
• Closed-loop speed control
• Speed curve configuration via EEPROM I2C serial port
• Sinusoidal modulation for reduced audible noise and low vibration
• Sensorless (no Hall sensors required)
• Low RDS(ON) power MOSFETs—3 A capability
• Minimal external components
• PWM speed input
• FG speed output
• RD rotor lock output
• Lock detection
• Soft start
• Standby mode
• Shorted load protection