Automotive Three Phase MOSFET Driver


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The A4939 is a three-phase controller for use with N-channel external power MOSFETs and is specifically designed for automotive applications.

A unique charge pump regulator provides full (>10 V) gate drive at battery voltages down to 7 V and allows the A4939 to operate with reduced gate drive at battery voltages down to 5.5 V. A bootstrap capacitor is used to provide the above battery supply voltage required for N-channel MOSFETs.

One logic level input is provided for each of the six power MOSFETs in the 3-phase bridge, allowing motors to be driven with any commutation scheme defined by an external controller. The power MOSFETs are protected from cross-conduction by integrated crossover control.

Motor phase short-to-supply and short-to-ground detection is provided by independent drain-source voltage monitors on each MOSFET. Short faults, supply undervoltage, and chip overtemperature conditions are indicated by a single open drain fault output.

Allegro recommended automotive qualified hall latches: APS122x5 and APS122x0

Product variants incorporating a low drop out (LDO) regulator to source either 5.0 V or 3.3 V to external circuitry are available. The A4939 is supplied in a 28-pin TSSOP power package with an exposed thermal pad (package type LP). This package is lead (Pb) free, with 100% matte tin leadframe plating (suffix T).


  • Electronic power steering (EPS, EHPS, EAS)
  • Hydraulic pumps
  • Engine cooling fan
  • Gearbox actuator
  • High current 3-phase gate drive for N-channel MOSFETs
  • Cross-conduction protection
  • 5.5 to 50 V supply voltage range
  • Regulated logic supply voltage output option
  • Motor phase short to supply and short to ground detection
  • Undervoltage, overtemperature monitors
  • Low current Sleep mode option

28-pin TSSOP with exposed thermal pad (suffix LP)

LP Package Documentation

Part Number Specifications and Availability

Documentation and Resources


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Reverse Battery Protection Scheme for Automotive Applications