Automotive Three-Phase MOSFET Driver


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The A4918 is an N-channel power MOSFET driver capable of controlling MOSFETs connected in a 3-phase bridge arrangement and is specifically designed for automotive applications with high-power inductive loads, such as BLDC motors. A unique charge pump regulator provides the supply for the MOSFET gate drive for battery voltages down to 7 V and allows the A4918 to operate with a reduced gate drive down to 4.5 V. Gate drive voltage and strength are programmable to help reduce EMC issues. A bootstrap capacitor is used to provide the above-battery supply voltage required for N-channel MOSFETs with an additional above-battery charge pump to ensure that the bootstrap capacitors remain charged when held in the on state. Full control is provided over all six power MOSFETs in the 3-phase bridge, allowing motors to be driven with block commutation or sinusoidal excitation.

The power MOSFETs are protected from shoot-through by integrated crossover control and optional programmable dead time. Integrated diagnostics provide indication of multiple internal faults, system faults, and power bridge faults, and can be configured to protect the power MOSFETs under most short circuit conditions. For safety-critical systems, the integrated diagnostic operation can be verified under control of the serial interface. The serial interface is provided to alter programmable settings and read back detailed diagnostic information.

Allegro recommended automotive-qualified Hall latches: APS122x5 and APS122x0

The A4918 is supplied in a 48-lead QFP package with exposed thermal pad as well as a in a new 7x7 48L QFN package with exposed thermal pad (reducing the PCB footprint by ~40%). These packages are lead (Pb) free with 100% matte tin leadframe plating.


A4918 was developed in accordance with ISO 26262:2011 as a hardware safety element out of context with ASIL D capability for use in automotive safety-related systems when integrated and used in the manner prescribed in the applicable safety manual and datasheet.
  • 3-phase bridge MOSFET driver
  • Bootstrap gate drive for N-channel MOSFET bridge
  • Cross-conduction protection with adjustable dead time
  • Charge pump for low supply voltage operation
  • Programmable gate drive voltage and strength
  • 4.5 to 50 V supply voltage operating range
  • Integrated logic supply
  • Three programmable current sense amplifiers
  • SPI-compatible serial interface
  • Bridge control by direct logic inputs or serial interface
  • Extensive programmable diagnostics
  • Diagnostic verification
  • Safety assist features
  • Automotive AEC-Q100 qualified

48-pin QFN with exposed thermal pad and wettable flank (suffix EV)

EV Package Documentation


48-pin LQFP with exposed thermal pad (suffix JP)

JP Package Documentation

Part Number Specifications and Availability

Documentation and Resources


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