A4942 Series

By Allegro MicroSystems, LLC 140

A4942 Series

Allegro's A4942 is a three phase sensorless brushless DC motor driver designed for fan and blower applications. Key applications include industrial and office automation fans such as those found in network servers. Key advantages include sensorless commutation, closed loop speed control, minimum and maximum speed settings, soft switching, adjustable soft start, adjustable phase advance, over current PWM protection, and small 20L 4 mm x 4 mm QFN package (ES).

  • Sensorless commutation control (no Hall sensors)
  • Closed loop speed control to insure predictable fan performance
  • Minimal external components to save PCB space and BOM cost
  • Adjustable soft start for reduced peak current demand
  • Adjustable soft switching to reduce fan audible noise
  • FG (speed) output
  • Adjustable startup oscillator to fit multiple motors and loads
  • Internal PWM current limit control with or without external sense resistor
  • Small PCB footprint 4 mm x 4 mm QFN package

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