A4939: Automotive Three Phase MOSFET Driver

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Top Features

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

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check Stock
APEK4939KLP-01-T DEMO BOARD -20°C to 85°C No -- Contact your
local sales rep
Distributor Stock
A4939KLPTR-5-T 28-lead TSSOP -40°C to 150°C Yes View Data Contact your
local sales rep
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.

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A4939 Demo board Schematic/Layout