FEATURES AND BENEFITS

Three-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

• Top-off charge pump for 100% PWM

• Programmable gate drive voltage and strength

• 5.5 to 50 V supply voltage operating range

• Integrated logic supply

• Logic level phase state outputs

• Three current sense amplifiers

• Programmable gain and offset with offset output

• SPI-compatible serial interface

• Bridge control by direct logic inputs or serial interface

• TTL compatible logic inputs

• Extensive programmable diagnostics

• Diagnostic verification

• Safety-assist features

• Automotive AEC-Q100 qualified

• A2-SIL™ product—device features for safety-critical systems

DESCRIPTION

The A4911 is an N-channel power MOSFET driver capable

of controlling MOSFETs connected in a three-phase bridge

arrangement and is specifically designed for automotive

applications with high-power inductive loads, such as BLDC

motors.

The A4911 is intended for automotive systems that must

meet ASIL requirements. In common with other Allegro

A2-SIL™ products, it incorporates features to complement

proper system design, allowing users to achieve up to ASIL D

system classification.

A unique charge pump regulator provides the supply for the

MOSFET gate drive for battery voltages down to 7 V and

allows the A4911 to operate with a reduced gate drive down

to 5.5 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.

Full control over all six power MOSFETs in the three-phase

bridge is provided, 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.

The A4911 is supplied in a 48-terminal wettable flank QFN package

(suffix EV) and a 48-pin QFP package (suffix JP), both with exposed

thermal pad. These packages are lead (Pb) free with 100% matte-tin

leadframe plating