A4957 Full Bridge MOSFET Driver Features and Benefits Description High current gate drive for N-channel MOSFET full bridge The A4957 is a full-bridge controller for use with external Independent control of each MOSFET N-channel power MOSFETs and is specifically designed for Charge pump for low supply voltage operation applications with high-power inductive loads such as brush Cross-conduction protection with adjustable dead time DC motors. 4.5 to 50 V supply voltage range A unique charge pump regulator provides full ( >10 V ) gate Diagnostics output drive for battery voltages down to 7 V and allows the A4957 Low current sleep mode 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 Package: 24-contact QFN with exposed capacitor is always sufficiently charged to supply the high-side thermal pad (Suffix ES) 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). Not to scale Typical Application VBAT FAULT AHI BHI A4957 M ALO BLO A4957-DSA4957 Full Bridge MOSFET Driver Selection Guide Part Number Packing A4957SESTR-T 1500 pieces per reel Absolute Maximum Ratings* Characteristic Symbol Notes Rating Unit Load Supply Voltage V 0.3 to 50 V BB Logic Supply Voltage V 0.3 to 7 V DD Logic Inputs V 0.3 to 6.5 V I Logic Outputs V 0.3 to 6.5 V O Pin VREG V 0.3 to 16 V VREG Pins CP1, CP2 V 0.3 to 16 V CPX Pin RDEAD V 0.3 to 6.5 V RDEAD Pins SA, SB V 5 to 55 V SX Pins GHA, GHB V V to V + 15 V GHX SX SX Pins GLA, GLB V 5 to 16 V GLX Pins CA, CB V 0.3 to V +15 V CX SX ESD Rating, Human Body Model AEC Q100-002, all pins 2000 V ESD Rating, Charged Device Model AEC Q100-011, all pins 1000 V Ambient Operating Temperature T Range S 20 to 85 C A Range Continuous Junction Temperature T (max) 150 C J Overtemperature event not exceeding Transient Junction Temperature T 10 s, lifetime duration not exceeding 10 hr, 175 C Jt guaranteed by design characterization Storage Temperature Range T 55 to 150 C stg *With respect to ground Thermal Characteristics may require derating at maximum conditions, see application information Characteristic Symbol Test Conditions* Value Unit Package Thermal Resistance, Junc- R Estimated, on 4-layer PCB based on JEDEC standard 37 C/W JA tion to Ambient Package Thermal Resistance, Junc- R 2 C/W JP tion to Pad *Additional thermal information available on the Allegro website Allegro MicroSystems, LLC 2 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000 www.allegromicro.com
