QuietMotion BLDC Gate Driver with Integrated FOC for Automotive Fans and Pumps - A89307 | Allegro MicroSystems




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The A89307 is a 3-phase, sensorless, BLDC gate driver that can operate from 5.5 to 45 V. A fully integrated field-oriented control (FOC) algorithm makes it easy to improve efficiency and acoustic noise performance, with no software programming or code development required. Designed for battery cooling fans and HVAC systems in EV and hybrid vehicles, the A89307 offers ultra-low noise and vibration courtesy of its continuous sinusoidal drive current, making it ideal for fans.

Modes of operation include open-loop PWM or fully programmable closed-loop speed control. In closed-loop mode, the customer can program the PWM-to-speed relationship to match the PWM commands provided by an external ECU. Field weakening is included to improve performance at high speed. Low-speed operation and windmilling start-up are just a few of the features included in the A89307 hardware based digital algorithm. 

With only five external components and available in a 28L wettable flank QFN package, the A89307 helps designers lower material costs by reducing BOM sizes and facilitating very small system footprints for in-motor PCBs. Its fully integrated algorithm can even eliminate the need for a separate microprocessor.  Closed loop speed control with analog, PWM or Clock based control as well as custom programming of input command to speed output allows for easy integration with multiple OEM ECU interfaces.

While designed for xEV battery cooling fans, the A89307 can also be used in HVAC blowers as well as liquid pumps in traction inverter cooling systems. The external gate drive allows the device to be flexible enough to drive a wide range of motor powers up to 500W. 

  • Code-free sensorless field-oriented control (FOC) - No software programming
  • Ultra-quiet low speed operation - Reduces audible noise and vibration
  • Proprietary non-reverse fast startup - Improves reliability and reduces audible noise
  • Analog, PWM, Analog, or Clock mode speed control with programmable speed profile
  • Configurable current limit and lock detection - Reduces motor heating
  • Start-up under both forward and reverse windmilling conditions - improves reliability
  • Short-circuit protection (OCP) - protects supply and PCB from burning during MOSFET failure

 Typical Applications:

  • Battery Cooling Fan
  • HVAC Fan
  • Inverter Cooling Pump

28L Wettable Flank QFN (suffix ET)

ET Packaging Documentation

Part Number Specifications and Availability

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