A4957_16 Datasheet, PDF (1/16 Pages) Allegro MicroSystems – Full Bridge MOSFET Driver

A4957
Full Bridge MOSFET Driver
Features and Benefits
▪ High current gate drive for N-channel MOSFET full bridge
▪ Independent control of each MOSFET
▪ Charge pump for low supply voltage operation
▪ Cross-conduction protection with adjustable dead time
▪ 4.5 to 50 V supply voltage range
▪ Diagnostics output
▪ Low current sleep mode
Package: 24-contact QFN with exposed
thermal pad (Suffix ES)
Not to scale
Description
The A4957 is a full-bridge controller for use with external
N-channel power MOSFETs and is specifically designed for
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 A4957
to operate with a reduced gate drive, down to 4.5 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 A4957 is supplied in a 24-contact 4 mm × 4 mm × 0.75 mm
QFN with an exposed pad for enhanced thermal dissipation.
It is lead (Pb) free, with 100% matte tin leadframe plating
(suffix –T).
A4957-DS
Typical Application
FAULT
AHI
BHI
ALO
BLO
A4957
VBAT
M