A4940
Automotive Full Bridge MOSFET Driver
Features and Benefits
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High current gate drive for N-channel MOSFET full bridge
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Independent control of each MOSFET
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Charge pump for low supply voltage operation
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Cross-conduction protection with adjustable dead time
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5.5 to 50 V supply voltage range
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Diagnostics output
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Low current sleep mode
Description
The A4940 is a full-bridge controller for use with external
N-channel power MOSFETs and is specifically designed for
automotive applications with high-power inductive loads such
as brush DC motors.
A unique charge pump regulator provides full ( >10 V ) gate
drive for battery voltages down to 7 V and allows the A4940
to operate with a reduced gate drive, down to 5.5 V.
A bootstrap capacitor is used to provide the above battery
supply voltage required for N-channel MOSFETs. A unique
bootstrap charge management system ensures that the bootstrap
capacitor is always sufficiently charged to supply the high-side
gate drive circuit.
Each of the power MOSFETs is controlled independently but
all are protected from shoot-through by dead time that is user-
configured by an external resistor.
Integrated diagnostics provide indication of undervoltage and
overtemperature faults.
The A4940 is supplied in a 24-pin TSSOP power package with
an exposed pad for enhanced thermal dissipation (package
type LP). It is lead (Pb) free, with 100% matte tin leadframe
plating (suffix –T).
Package: 24-pin TSSOP with exposed
thermal pad (suffix LP)
Not to scale
Typical Application
FAULT
VBAT
AHI
BHI
A4940
M
ALO
BLO
A4940-DS
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
