A4957: Full Bridge MOSFET Driver

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 userconfigured 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).


Astrorep Inc. (Allegro and Sanken Semiconductors, Sanken Power Supplies)
141 John Street, Suite 300
Babylon, NY 11702
Phone: (631)422-2500
Fax: (631)422-2504
Web: www.astrorepinc.com
Email: donna.tweedy@astrorepinc.com

If this is not your local representative, find your local sales rep here.

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  • Features and BenefitsFeatures and Benefits
  • PackagingPackaging
  • Technical DocsTechnical Docs
  • NewsNews
  • 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

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Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check
Distributor Stock
A4957SESTR-T 24-lead QFN -20°C to 85°C Yes View Data Contact your
local sales rep
Check Stock
APEK4957SES-01-T DEMO BOARD -20°C to 85°C No -- Contact your
local sales rep
Check Stock

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